Existing Cohort Study Research Articles

Gender Specific Differences in COVID-19 Knowledge, Behavior and Health Effects Among Adolescents and Young Adults in Uttar Pradesh and Bihar, India

Background: On March 24, 2020 India implemented a national lockdown to prevent spread of the novel Coronavirus disease (COVID-19) among its 1.3 billion people. The pandemic may disproportionately impact women and girls. This study examines gender differences in knowledge of COVID-19 symptoms and preventive behaviors, as well as the adverse secondary health effects of the lockdown.Methods: A mobile phone-based survey was implemented from April 3-22, 2020 in Uttar Pradesh and Bihar among respondents randomly selected from an existing cohort study. Respondents answered questions related to demographics, COVID-19 knowledge, attitudes, and preventive behaviors practiced, and impacts on social, economic and health outcomes. Descriptive analyses and linear probability regression models were performed for all participants and separately for males and females.Findings: 1,666 adolescent and young adults (18-24 years old) were surveyed; 70% female. While most participants had high awareness of disease symptoms and preventive behaviors, there was variation by gender. Compared to males, females were seven percentage points (pp) less likely to know the main symptoms of COVID-19 (coeff = -0·071; 95% confidence interval: -0·122 - -0·021). Among females, there was variation by education level, urban residence, and household wealth. Females were 22 pp less likely to practice key preventive behaviors (coeff = -0·222; 95% CIL -0·263, -0·181); among female respondents, knowledge was the only factor significantly associated with doing the behaviors. Females were more likely to report recent depressive feelings than males (coeff =0·057; 95% CI: 0·004, 0·109).Interpretation: Wide gender gaps in knowledge, adoption of preventive behaviors, and adverse mental health effects were identified, indicating that COVID-19 is already disproportionately impacting adolescent and young women. Gender-sensitive information campaigns and provision of health services must be accessible and provide support during the pandemic to ensure gains in public health and gender equity are not lost.Funding: None.Declaration of Interests: The authors have no personal or financial relationships to disclose.Ethics Approval Statement: We received expedited ethical approval from the Population Council’s Institutional Review Board (IRB) by meeting criteria for research conducted during COVID-19. The IRB permitted data collection with existing cohorts for participants with previous consent provided the research aligned with national mitigation efforts. The UDAYA study protocol originally received IRB approval in 2015 for longitudinal data collection. Participants were told they could terminate the study at any time or skip any sections. No incentives were offered for taking part in the study.

Application of the matched nested case-control design to the secondary analysis of trial data

BackgroundA nested case-control study is an efficient design that can be embedded within an existing cohort study or randomised trial. It has a number of advantages compared to the conventional case-control design, and has the potential to answer important research questions using untapped prospectively collected data.MethodsWe demonstrate the utility of the matched nested case-control design by applying it to a secondary analysis of the Abnormal Doppler Enteral Prescription Trial. We investigated the role of milk feed type and changes in milk feed type in the development of necrotising enterocolitis in a group of 398 high risk growth-restricted preterm infants.ResultsUsing matching, we were able to generate a comparable sample of controls selected from the same population as the cases. In contrast to the standard case-control design, exposure status was ascertained prior to the outcome event occurring and the comparison between the cases and matched controls could be made at the point at which the event occurred. This enabled us to reliably investigate the temporal relationship between feed type and necrotising enterocolitis.ConclusionsA matched nested case-control study can be used to identify credible associations in a secondary analysis of clinical trial data where the exposure of interest was not randomised, and has several advantages over a standard case-control design. This method offers the potential to make reliable inferences in scenarios where it would be unethical or impractical to perform a randomised clinical trial.

Undiagnosed dementia in primary care: a record linkage study

Background The number of people living with dementia is greater than the number with a diagnosis of dementia recorded in primary care. This suggests that a significant number are living with dementia that is undiagnosed. Little is known about this group and there is little quantitative evidence regarding the consequences of diagnosis for people with dementia. Objectives The aims of this study were to (1) describe the population meeting the criteria for dementia but without diagnosis, (2) identify predictors of being diagnosed and (3) estimate the effect of diagnosis on mortality, move to residential care, social participation and well-being. Design A record linkage study of a subsample of participants (n = 598) from the Cognitive Function and Ageing Study II (CFAS II) (n = 7796), an existing cohort study of the population of England aged ≥ 65 years, with standardised validated assessment of dementia and consent to access medical records. Data sources Data on dementia diagnoses from each participant’s primary care record and covariate and outcome data from CFAS II. Setting A population-representative cohort of people aged ≥ 65 years from three regions of England between 2008 and 2011. Participants A total of 598 CFAS II participants, which included all those with dementia who consented to medical record linkage (n = 449) and a stratified sample without dementia (n = 149). Main outcome measures The main outcome was presence of a diagnosis of dementia in each participant’s primary care record at the time of their CFAS II assessment(s). Other outcomes were date of death, cognitive performance scores, move to residential care, hospital stays and social participation. Results Among people with dementia, the proportion with a diagnosis in primary care was 34% in 2008–11 and 44% in 2011–13. In both periods, a further 21% had a record of a concern or a referral but no diagnosis. The likelihood of having a recorded diagnosis increased with severity of impairment in memory and orientation, but not with other cognitive impairment. In multivariable analysis, those aged ≥ 90 years and those aged < 70 years were less likely to be diagnosed than other age groups; those living with a spouse (odds ratio 2.38, 95% confidence interval 1.04 to 5.41) were more likely to be diagnosed than people living alone. The median time to diagnosis from first meeting the criteria for dementia was 3 years. Diagnosis did not affect survival or the probability of a move to residential care. Limitations People with moderate to severe dementia at baseline could not consent to record linkage. The small numbers in some groups limited power to detect effects. Conclusions The lack of relationship between severity of non-memory impairment and diagnosis may reflect low awareness of other symptoms of dementia. There remains little objective evidence for benefits of diagnosis for people with dementia. Future work Potential benefits of diagnosis can be realised only if effective interventions are accessible to patients and carers. Future work should focus on improving support for people living with cognitive impairment. Study registration National Institute for Health Research Clinical Research Network Central Portfolio Management System (CPMS 30655). Funding This project was funded by the National Institute for Health Research (NIHR) Health Services and Delivery Research programme and will be published in full in Health Services and Delivery Research; Vol. 8, No. 20. See the NIHR Journals Library website for further project information.

Community norms for the Eating Disorder Examination Questionnaire (EDE-Q) among transgender men and women

Transgender men and women may be at risk for eating disorders, but prior community norms of the Eating Disorders Examination Questionnaire (EDE-Q) are based on presumed cisgender men and woman and have not intentionally included transgender people. The objective of this study was to develop community norms for eating disorder attitudes and disordered eating behaviors in transgender men and women using the EDE-Q. Participants were 312 transgender men and 172 transgender women participants in The PRIDE Study, an existing cohort study of sexual and gender minority people. We present mean scores, standard deviations, and percentile ranks for the Global score and four subscale scores of the EDE-Q in transgender men and women. Transgender men and women reported any occurrence (≥1/week) of dietary restraint (25.0% and 27.9%), objective binge episodes (11.2% and 12.8%), excessive exercise (8.0% and 8.1%), self-induced vomiting (1.6% and 1.7%), and laxative misuse (.3% and .6%), respectively. Compared to a prior study of presumed cisgender men 18–26 years (Lavender, De Young, & Anderson, 2010), our age-matched subsample of transgender men reported lower rates of objective binge episodes and excessive exercise. Compared to a prior study of presumed cisgender women 18–42 years (Mond, Hay, Rodgers, & Owen, 2006), we found that an age-matched sample of transgender women reported higher rates of dietary restraint but lower rates of excessive exercise. These norms should aid clinicians in applying and researchers in investigating and interpreting the EDE-Q scores of transgender men and women.

Drinking motivations in UK serving and ex-serving military personnel.

BackgroundDrinking motivations within the UK military have not been studied despite the high prevalence of alcohol misuse in this group.AimsWe aimed to characterize drinking motivations and their demographic, military and mental health associations in UK serving and ex-serving personnel.MethodsServing and ex-serving personnel reporting mental health, stress or emotional problems occurring in the last 3 years were selected from an existing cohort study. A semi-structured telephone interview survey examined participants’ mental health, help-seeking, alcohol use and drinking motivations.ResultsExploratory factor analysis of drinking motivations in military personnel (n = 1279; response rate = 84.6%) yielded 2 factors, labelled ‘drinking to cope’ and ‘social pressure’. Higher drinking to cope motivations were associated with probable anxiety (rate ratio [RR] = 1.4; 95% confidence interval [CI] = 1.3–1.5), depression (RR = 1.3; 95% CI = 1.2–1.4) and post-traumatic stress disorder (RR = 1.4; 95% CI = 1.3–1.6). Higher social pressure motivations were associated with probable anxiety (odds ratio = 1.1; 95% CI = 1.0–1.1). Alcohol misuse and binge drinking were associated with reporting higher drinking to cope motivations, drinking at home and drinking alone.ConclusionsAmongst military personnel with a stress, emotional or mental health problem, those who drink to cope with mental disorder symptoms or because of social pressure, in addition to those who drink at home or drink alone, are more likely to also drink excessively.

The Victorian Intergenerational Health Cohort Study (VIHCS): Study design of a preconception cohort from parent adolescence to offspring childhood.

There is increasing evidence that parental determinants of offspring early life development begin well before pregnancy. We established the Victorian Intergenerational Health Cohort Study (VIHCS) to examine the contributions of parental mental health, substance use, and socio-economic characteristics before pregnancy to child emotional, physical, social, and cognitive development. Men and women were recruited from the Victorian Adolescent Health Cohort (VAHCS), an existing cohort study beginning in 1992 that assessed a representative sample of 1943 secondary school students in Victoria, Australia, repeatedly from adolescence (wave 1, mean age 14years) to adulthood (wave 10, mean age 35years). Victorian Adolescent Health Cohort participants with children born between 2006 and 2013 were recruited to VIHCS and invited to participate during trimester three, at 2months postpartum, and 1year postpartum. Parental mental health, substance use and socio-economic characteristics were assessed repeatedly throughout; infant characteristics were assessed postnatally and in infancy. Data will be supplemented by linkage to routine datasets. A further follow-up is underway as children reach 8years of age. Of the 1307 infants born to VAHCS participants between 2006 and 2013, 1030 were recruited to VIHCS. At VIHCS study entry, 18% of recruited parents had preconception common mental disorder in adolescence and young adulthood, 18% smoked daily in adolescence and young adulthood, and 6% had not completed high school. Half of VIHCS infants were female (48%), 4% were from multiple births, and 7% were preterm (<37weeks' gestation). Victorian Intergenerational Health Cohort Study is a prospective cohort of 1030 children with up to nine waves of preconception parental data and three waves of perinatal parental and infant data. These will allow examination of continuities of parental health and health risks from the decades before pregnancy to offspring childhood, and the contributions of exposures before pregnancy to offspring outcomes in childhood.

Relations between air pollution and vascular development in 5-year old children: a cross-sectional study in the Netherlands

BackgroundAir pollution has been shown to promote cardiovascular disease in adults. Possible mechanisms include air pollution induced changes in arterial wall function and structure. Atherosclerotic vascular disease is a lifelong process and childhood exposure may play a critical role. We investigated whether air pollution is related to arterial wall changes in 5-year old children. To this aim, we developed an air pollution exposure methodology including time-weighted activity patterns improving upon epidemiological studies which assess exposure only at residential addresses.MethodsThe study is part of an existing cohort study in which measurements of carotid artery intima-media thickness, carotid artery distensibility, elastic modulus, diastolic and systolic blood pressure have been obtained. Air pollution assessments were based on annual average concentration maps of Particulate Matter and Nitrogen Oxides at 5 m resolution derived from the European Study of Cohorts for Air Pollution Effects. We defined children’s likely primary activities and for each activity we calculated the mean air pollution exposure within the assumed area visited by the child. The exposure was then weighted by the time spent performing each activity to retrieve personal air pollution exposure for each child. Time spent in these activities was based upon a Dutch mobility survey. To assess the relation between the vascular status and air pollution exposure we applied linear regressions in order to adjust for potential confounders.ResultsCarotid artery distensibility was consistently associated with the exposures among the 733 5-years olds. Regression analysis showed that for air pollution exposures carotid artery distensibility decreased per standard deviation. Specifically, for NO2, carotid artery distensibility decreased by − 1.53 mPa− 1 (95% CI: -2.84, − 0.21), for NOx by − 1.35 mPa− 1 (95% CI: -2.67, − 0.04), for PM2.5 by − 1.38 mPa− 1 (95% CI: -2.73, − 0.02), for PM10 by − 1.56 mPa− 1 (95% CI: -2.73, − 0.39), and for PM2.5absorbance by − 1.63 (95% CI: -2.30, − 0.18). No associations were observed for the rest outcomes.ConclusionsThe results of this study support the view that air pollution exposure may reduce arterial distensibility starting in young children. If the reduced distensibility persists, this may have clinical relevance later in life. The results of this study further stress the importance of reducing environmental pollutant exposures.

Living with multimorbidity? The lived experience of multiple chronic conditions in later life.

Multimorbidity is defined biomedically as the co-existence of two or more long-term conditions in an individual. Globally, the number of people living with multiple conditions is increasing, posing stark challenges both to the clinical management of patients and the organisation of health systems. Qualitative literature has begun to address how concurrency affects the self-management of chronic conditions, and the concept of illness prioritisation predominates. In this article, we adopt a phenomenological lens to show how older people with multiple conditions experience illness. This UK study was qualitative and longitudinal in design. Sampling was purposive and drew upon an existing cohort study. In total, 15 older people living with multiple conditions took part in 27 in-depth interviews. The practical stages of analysis were guided by Constructivist Grounded Theory. We argue that the concept of multimorbidity as biomedically imagined has limited relevance to lived experience, while concurrency may also be erroneous. In response, we outline a lived experience of multiple chronic conditions in later life, which highlights differences between clinical and lay assumptions and makes the latter visible.

Commentary on Costanzo et al. (2019): The need for secondary analyses of prospective cohort studies—creating a better understanding of alcohol consumption and hospitalization

The risk relationsip between alcohol consumption and disease occurrence often differs depending on whether the end-point used is mortality or morbidity. More studies using morbidity as an end-point are required to avoid incorrect results when estimating the burden of alcohol-related harm. Cohort study networks offer opportunities for conducting such studies. Alcohol consumption is a leading risk factor for the burden of disease 1, 2, and a large proportion of the alcohol-attributable burden is due to disability and impaired functioning 1-3. However, the majority of cohort studies which examine the risk relationship (RR) between alcohol consumption and disease occurrence use mortality as an end-point 4 because mortality is easier to assess as its recording is often mandated by law, while the measurement of non-fatal end-points are more resource-intensive to collect and often are not mandated by law 4, 5. For example, studies using hospitalization as an end-point require a central collection and collation of hospitalization records, and for these records to be linked to a unique personal identifier. However, in many countries and regions, hospitalization services are administered by multiple companies with different data access and data organization policies. Under such circumstances, the resources needed to collect and harmonize hospitalization data from multiple sources are often cost- and resource-prohibitive. Consequently, for meta-analyses, data on the effects of alcohol on morbidity alone are not sufficiently available to produce accurate and precise RR estimates. Accordingly, for most disease conditions, meta-analyses combine studies which use mortality and morbidity as end-points 3, 4. Previous studies have found evidence that the alcohol RRs for various chronic diseases 6-9 may differ depending on whether mortality or morbidity is used as the end-point. In line with this, the Moli-sani study differs from mortality-based studies 3, 19 in that heavy alcohol consumers were found not to be at an increased risk of hospitalization from ischaemic heart disease and cerebrovascular accidents. These differences in the RRs by disease end-point are due to potentially confounding factors (e.g. the stage at which the diseases are diagnosed and treated, access to health care, heavy drinkers avoiding hospitals due to stigmatization by health-care workers 10-14 and/or factors affected by alcohol consumption (e.g. adherence to treatment regimens 15. Therefore, the combining of mortality and morbidity RRs may lead to incorrect results in studies which utilize both these RRs, such as the 2018 Global Status Report on Alcohol and Health 1, the 2017 Global Burden of Disease study 2 and other studies which have estimated hospitalizations and hospitalization costs attributable to alcohol 16-18. The data analysis of the Moli-sani study by Costanzo and colleagues 19 demonstrates the availability of opportunities to perform analyses of cohort studies which are linked to hospital discharge registries. As a result of the observation that there are different alcohol RRs for morbidity and mortality, there is a need for additional analyses of cohort studies linked to hospitalization records to examine the association of alcohol with specific alcohol-related diseases. Such analyses could take advantage of existing cohort study networks. An example of a large cohort study network is the European Prospective Investigation into Cancer and Nutrition (of which the Moli-sani study is a participant). Although this cohort study network was originally designed to examine the RRs for various risk factor exposures and the development of cancer, such a network can be used for the secondary purpose of assessing the RR for alcohol consumption and hospitalization. These sorts of analyses will lead to improvements in our understanding of how alcohol consumption leads to disease occurrence and, further, will improve the evidence base for studies which model how best to reduce morbidity, hospitalizations and hospital costs due to alcohol consumption. None. K.D.S. receives funding from the 2018 Canadian Institutes of Health Research - Institute of Population and Public Health Trailblazer Award in Population and Public Health Research.

197. Markers of maternal cardiac dysfunction in pre-eclampsia and superimposed pre-eclampsia

Introduction Women who experience hypertensive disorders of pregnancy have an increased risk of developing cardiovascular disease in later life. The mechanism underlying this association unknown. Objectives To determine whether elevated glycogen phosphorylase isoenzyme B (GPBB) and/or brain natriuretic peptide (BNP) concentrations suggestive of cardiac dysfunction are observed in pre-eclampsia and superimposed pre-eclampsia (SPE). Method Four groups of women were selected from an existing cohort study: healthy controls (n = 21), pre-eclampsia (n = 19), pre-existing chronic hypertension (CHT) and/or chronic kidney disease (CKD) without (n = 20), or with SPE (n = 19). Plasma samples taken in the third trimester or at time of disease were assayed using Diagenics Dianeonatal® Glycogen phosphorylase Isoenzyme BB (GP-BB)-ELISA in vitro diagnostic device kits and Alere Triage © CardioRenal assays (BNP). Log transformed GPBB and BNP concentrations were compared using interval regression as ratios of the geometric means with 95% confidence intervals. Results No difference was observed in GPBB plasma concentrations between the control and pre-eclampsia groups (mean [95% C.I.]: 4.72 [2.49–8.94] ng/mL vs 4.98 [2.52–9.84] ng/mL; N = 40, p = 0.91), or between CHT and/or CKD and SPET groups (mean [95% C.I.]: 9.49 [4.93–18.25] ng/mL vs 10.24 [5.27–19.92] ng/mL; N = 39, p = 0.87). BNP plasma concentrations were significantly raised in the pre-eclampsia group compared to the control group (mean [95% C.I.]: 31.75 [19.21–52.49] pg/mL vs 11.31 [7.00–18.25] pg/mL; N = 40, p = 0.004), but did not reach statistical significance between the SPET and CHT and/or CKD groups (GM [95% C.I.]: 20.66 [12.40–34.44] pg/mL vs 16.06 [9.83–26.23] pg/mL; N = 39, p = 0.486). Discussion There was no difference in GPBB concentration between groups. BNP concentrations were elevated in cases of pre-eclampsia compared to controls. This suggests cardiac dysfunction at the time of pre-eclampsia but through a mechanism other than cardiac ischaemia, and little role for the use of GPBB as a biomarker in hypertensive disorders of pregnancy.

Outcome-related, Auxiliary Variable Sampling Designs for Longitudinal Binary Data.

Epidemiologists have long used case-control and related study designs to enhance variability of response and information available to estimate exposure-disease associations. Less has been done for longitudinal data. We discuss an epidemiological study design and analysis approach for longitudinal binary response data. We seek to gain statistical efficiency by oversampling relatively informative subjects for inclusion into the sample. In this methodological demonstration, we develop this concept by sampling repeatedly from an existing cohort study to estimate the relationship of chronic obstructive pulmonary disease to past-year smoking in a panel of baseline smokers. To account for oversampling, we describe a sequential offsetted regressions approach for valid inferences in this setting. Targeted sampling can lead to increased statistical efficiency when combined with sequential offsetted regressions. Efficiency gains are degraded with increased prevalence of the disease response variable, with decreased association between the sampling variable and the response, and with other design and analysis parameters, providing guidance to those wishing to use these types of designs in the future. These designs hold promise for efficient use of resources in longitudinal cohort studies.

The dynamics of epidural and opioid analgesia during labour.

To investigate the association of analgesia, opioids or epidural, or the combination of both with labour duration and spontaneous birth in nulliparous women. A secondary data analysis of an existing cohort study was performed and included nulliparous women (n=2074). Durations of total labour and first and second labour stage were calculated with Kaplan-Meier estimation for the four different study groups: no analgesia (n=620), opioid analgesia (n=743), epidural analgesia (n=482), and combined application (n=229). Labour duration was compared by Cox regression while adjusting for confounders and censoring for operative births. Logistic regression was used to investigate the association between the administration of different types of analgesia and mode of birth. Most women in the combined application group were first to receive opioid analgesia. Women with no analgesia had the shortest duration of labour (log rank p<0.001) and highest chance of a spontaneous birth (p<0.001). If analgesia was administered, women with opioids had a shorter first stage (p=0.018), compared to women with epidural (p<0.001) or women with combined application (p<0.001). Women with opioids had an increased chance to reach full cervical dilatation (p=0.006). Women with epidural analgesia (p<0.001) and women with combined application (p<0.001) had a prolonged second stage and decreased chance of spontaneous birth compared to women without analgesia. Women with opioids had a prolonged first stage, but increased chance to reach full cervical dilatation. Women with epidural analgesia and women with both opioid and epidural analgesia had a prolonged first and second stage and a decreased chance of a spontaneous birth.

Labour duration and timing of interventions in women planning vaginal birth after caesarean section

Objectiveunderstanding the labour characteristics of women attempting vaginal birth after caesarean (VBAC) may suggest how to improve intrapartum management and may enhance success rates. Promoting VBAC is a relevant factor in decreasing overall caesarean section (c-section) rates. However, the labour processes of women attempting VBAC are not well investigated. The aim of this paper is to compare multiparae planning a first VBAC (pVBAC) with primiparae and with multiparae planning a second vaginal birth, all starting to give birth vaginally, with regard to (a) perinatal characteristics, (b) the timing of intrapartal spontaneous rupture of membranes (SROM) and of interventions, and (c) labour duration, with respect to the first and second stages. Settingcohort study of women planning vaginal birth in 47 obstetric units in Lower Saxony, Germany. Participants1897 primiparae, 211 multiparae with one previous c-section and 1149 multiparae with one previous vaginal birth. Measurementssecondary analysis of data from an existing cohort study. Kaplan–Meier estimates, log rank test, Wilcoxon test and shared frailty Cox regression models including time-varying covariates were used to compare the timing of interventions and labour duration between the subsamples. Analyses were done with the statistics programme Stata 13. Findingsperinatal and labour characteristics of multiparae with pVBAC mainly resembled those of primiparae and differed from those of multiparae planning a second vaginal birth. However, compared to primiparae, multiparae with pVBAC received oxytocin less often (48.82 versus 56.95%, p=0.024) and gave birth vaginally significantly less often (69.19 versus 83.40%, p<0.001). The timing of intrapartal SROM (2.67 versus 3.42 hours, p=0.112) and of interventions (amniotomy: 5.50 versus 5.83 hours, p=0.198; oxytocin: 5.75 versus 6.00 hours, p=0.596; epidural: 4.00 versus 4.67 hours, p=0.416; opioids: 3.83 versus 3.78, p=0.851) was similar to that in primiparae although timings of all interventions but not of SROM differed significantly from that in multiparae with second vaginal birth (SROM: 2.67 versus 2.67 hours, p=0.481; amniotomy: 5.50 versus 3.93 hours, p<0.001; oxytocin: 5.75 versus 4.25 hours, p<0.001; epidural: 4.00 versus 3.50 hours, p=0.009; 3.83 versus. 2.75 hours, p=0.026). Overall and first-stage labour duration were comparable to primiparae (overall labour duration: 8.83 versus 8.57 hours, HR=0.998, 95% CI=0.830−1.201, p=0.987; first stage: 7.42 versus 7.00 hours, HR=0.916, 95% CI=0.774-1.083, p=0.303) but significantly longer than in other multiparae (overall labour duration: 8.83 versus 4.63 hours, HR=0.319, 95% CI=0.265−0.385, p<0.001; first stage: 7.42 versus 4.25 hours, HR=0.402, 95% CI=0.339-0.478, p<0.001). However, the second stage of labour was significantly shorter in multiparae with pVBAC than in primiparae (0.55 versus 0.77 hours, HR=1.341, 95% CI=1.049−1.714, p=0.019), but longer than in multiparae with second vaginal birth (0.55 versus 0.22 hours, HR=0.334, 95% CI=0.262–0.426, p<0.001). Key conclusionlabour patterns of multiparous women planning a VBAC differ from those of primiparae and other multiparous women. Multiparae with pVBAC should be considered as a distinct group of parturients. Implication for practiceexpectations regarding labour progression for multiparae with first pVBAC should be similar to those for primiparae. However, the chance that the second stage of labour might be shorter than in primiparae is relevant and motivating information for pregnant women with a previous c-section in deciding the planned mode of birth.

Association between Exposure to Environmental Tobacco Smoke and Biomarkers of Oxidative Stress Among Patients Hospitalised with Acute Myocardial Infarction

ObjectiveTo determine whether exposure to environmental tobacco smoke was associated with oxidative stress among patients hospitalised for acute myocardial infarction.DesignAn existing cohort study of 1,261 patients hospitalised for acute myocardial infarction.SettingNine acute hospitals in Scotland.ParticipantsSixty never smokers who had been exposed to environmental tobacco smoke (admission serum cotinine ≥3.0 ng/mL) were compared with 60 never smokers who had not (admission serum cotinine ≤0.1 ng/mL).InterventionNone.Main outcome measuresThree biomarkers of oxidative stress (protein carbonyl, malondialdehyde (MDA) and oxidised low-density lipoprotein (ox-LDL)) were measured on admission blood samples and adjusted for potential confounders.ResultsAfter adjusting for baseline differences in age, sex and socioeconomic status, exposure to environmental tobacco smoke was associated with serum concentrations of both protein carbonyl (beta coefficient 7.96, 95% CI 0.76, 15.17, p = 0.031) and MDA (beta coefficient 10.57, 95% CI 4.32, 16.81, p = 0.001) but not ox-LDL (beta coefficient 2.14, 95% CI −8.94, 13.21, p = 0.703).ConclusionsExposure to environmental tobacco smoke was associated with increased oxidative stress. Further studies are requires to explore the role of oxidative stress in the association between environmental tobacco smoke and myocardial infarction.

Determinants of Patient Satisfaction 1 Year After Presenting to Primary Care With Acute Low Back Pain

To determine predictors of satisfaction with care and symptoms in patients with acute low back pain 1 year after presentation to primary care. The study is a secondary analysis of an existing cohort study of 1343 patients with acute low back pain presenting to primary care. Participants presenting to general practitioners, physiotherapists, or chiropractors were assessed at the initial consultation and followed up over 12 months. Putative predictors of patient satisfaction were extracted from baseline questionnaires. Multivariate logistic regression models were developed to predict satisfaction with care and satisfaction with symptoms at the 12-month follow-up. Most patients were highly satisfied with the care received (76%) and a smaller proportion with their symptoms (55%) at 12 months. Pain intensity at 12 months had a strong association with both measures of satisfaction. After controlling for the level of pain intensity, those born outside Australia, older people, and those reporting more symptoms of depression were less likely to be satisfied with the care received. Patients reporting poor general health at the initial visit and more symptoms of depression were less likely to be satisfied with their symptoms at the 12-month follow-up. Pain intensity at the 12-month follow-up has a strong association with patient satisfaction. Primary care practitioners should remain aware of the influence of cultural, demographic, and psychological factors on satisfaction with care and symptoms.

Characteristics of Australian cohort study participants who do and do not take up an additional invitation to join a long-term biobank: The 45 and Up Study.

BackgroundLarge-scale population biobanks are critical for future research integrating epidemiology, genetic, biomarker and other factors. Little is known about the factors influencing participation in biobanks. This study compares the characteristics of biobank participants with those of non-participants, among members of an existing cohort study.MethodsIndividuals aged 45 and over participating in The 45 and Up Study and living ≤20km from central Wagga Wagga, New South Wales (NSW), Australia (rural/regional area) or ≤10km from central Parramatta, NSW (urban area) (n=2340) were invited to join a biobank, giving a blood sample and having additional measures taken, including height, weight, waist circumference, heart rate and blood pressure.ResultsThe overall uptake of the invitation to participate was 33% (762/2340). The response rate was 41% (410/1002) among participants resident in the regional area, and 26% (352/1338) among those resident in the urban area. Characteristics associated with significantly decreased participation were being aged 80 and over versus being aged 45–64 (participation rate ratio: RR = 0.45, 95%CI 0.34-0.60), not being born in Australia versus being born in Australia (0.69, 0.59-0.81), having versus not having a major disability (0.54, 0.38-0.76), having full-time caregiving responsibilities versus not being a full-time carer (0.62, 0.42-0.93) and being a current smoker versus never having smoked (0.66, 0.50-0.89). Factors associated with increased participation were being in part-time work versus not being in paid work (1.24, 1.07-1.44) and having an annual household income of ≥$50,000 versus <$20,000 (1.50, 1.26-1.80).ConclusionsA range of socio-economic, health and lifestyle factors are associated with biobank participation among members of an existing cohort study, with factors relating to health-seeking behaviours and access difficulties or time limitations being particularly important. If more widespread participation in biobanking is desired, particularly to ensure sufficient numbers among those most affected by these issues, specific efforts may be required to increase participation in certain groups such as migrants, the elderly, and those in poor health. Whilst caution should be exercised when generalising estimates of absolute prevalence from biobanks, estimates for many internal comparisons are likely to remain valid.

Randomised trial investigating the relationship of response rate for blood sample donation to site of biospecimen collection, fasting status and reminder letter: The 45 and Up Study

BackgroundVarious options exist for collecting biospecimens and biomarkers from cohort study participants, and these have important logistic, resource and scientific implications. Evidence on how different collection methods affect participation and data quality is lacking. This parallel-design randomised trial, the Link-Up Study, involved blood sample donation and other data collection among participants in an existing cohort study, The 45 and Up Study. It aimed to investigate the relation of fasting status, reminder letters and data collection site to response rates, data quality and biospecimen yield.MethodsIndividuals aged 45 and over participating in The 45 and Up Study and living ≤20 km from central Wagga Wagga, NSW (regional area) or ≤10 km from central Parramatta, NSW (urban area) (n = 2340) were randomised, stratified by area of residence, to be invited to give a blood sample and additional data by attending either a clinic established specifically for the trial, with an appointment time (“dedicated clinic”, n = 1336) or an existing local commercial pathology centre (n = 1004). Within dedicated clinic groups, participants were randomised into fasting (n = 668) or non-fasting (n = 668) and, at the Parramatta pathology centre site, reminder letter after two weeks (n = 336) or no reminder (n = 334).ResultsOverall, 33% (762/2340) of invitees took part in the Link-Up Study; 41% (410/1002) among regional and 26% (352/1338) among urban-area residents (p < 0.0001). At the dedicated clinics, response rates were 38% (257/668) not fasting and 38% fasting (257/668) (participation rate ratio (RR) = 1.00, 95%CI 0.91-1.08, p = 0.98). The response rate was 22% among individuals randomised to attend the Parramatta pathology centre without a reminder and 23% among those sent a reminder letter (RR = 1.01, 0.93-1.09, p = 0.74). In total, the response rate was 38% (514/1336) at the dedicated clinics and 25% (248/1004) at the pathology centres (RR = 0.67, 0.56-0.78, p < 0.01); measures of height, weight and systolic and diastolic blood pressure did not vary materially between these groups, nor did the median number of aliquots of plasma, buffy coat and red cells collected.ConclusionsAmong cohort study participants, response rates for an additional study involving biospecimen collection, but not data quality or average biospecimen yield, were considerably higher at dedicated clinics than at existing commercial pathology sites.

The Life Journeys of Young Women Project: Objectives, Design, and Recruitment Results

The Life Journeys of Young Women Project is the first population-based study to examine the role of economic uncertainty throughout early adulthood on age at first childbirth. A retrospective cross-sectional component was added to an existing cohort study that is based on a birth cohort of women born during 1973-1975 in Adelaide, South Australia (n ∼ 1,000). An event history calendar instrument was used to obtain data regarding a range of life domains including partnering, educational attainment, home ownership, higher education debt, employment, and pregnancies over a 20-year period (sometimes as detailed as at monthly intervals). Interviews were conducted between 2007 and 2009. An analysis framework applying time-varying and time-constant survival analysis techniques within a life-course framework was developed that will guide analyses to examine the role of duration and life-course timing of economic uncertainty on age at first childbirth. This paper discusses study objectives and design, fieldwork procedures, planned statistical analyses, and recruitment outcomes, focusing on novel features that would facilitate analogous epidemiologic research.

Predictors of Cognitive Decline in Older Individuals With Diabetes

OBJECTIVE—The purpose of this study was to determine longitudinal predictors of cognitive decline in older individuals with diabetes who did not have dementia.RESEARCH DESIGN AND METHODS—Cognitive assessments were performed in 205 subjects with diabetes (mean age 75.3 years) and repeated a median 1.6 years later. The sample was drawn from an existing cohort study, and data on diabetes, cardiovascular risk factors, and complications were collected 7.6 ± 1.1 years before and at the time of the initial cognitive assessment. Cognitive status was defined using the Clinical Dementia Rating (CDR) scale, and cognitive decline was defined by change in CDR.RESULTS—The sample included 164 subjects with normal cognition (CDR 0) and 41 with cognitive impairment without dementia (CDR 0.5). At follow-up, 33 (16.1%) had experienced cognitive decline (4 new cases of dementia and 29 cognitive impairment without dementia). Only educational attainment predicted cognitive decline from the data collected 7.6 years before cognitive assessment. Univariate predictors of cognitive decline at the time of the first cognitive assessment included age, education, urinary albumin-to-creatinine ratio (ACR), and treatment with either ACE inhibitors (ACEIs) or angiotensin receptor blockers (ARBs). With multiple logistic regression controlling for age and education, cognitive decline was predicted by natural logarithm ACR (odds ratio 1.37 [95% CI 1.05–1.78], P = 0.021), whereas treatment with either ACEIs or ARBs was protective (0.28 [0.12–0.65], P = 0.003).CONCLUSIONS—In this sample of older patients with diabetes, microalbuminuria was a risk factor for cognitive decline, whereas drugs that inhibit the renin-angiotensin system were protective. These observations require confirmation because of their considerable potential clinical implications.

Smoking and height as risk factors for prevalence and 5-year incidence of hearing loss. A questionnaire-based follow-up study of employees in Denmark aged 18–59 years exposed and unexposed to noise

This paper investigated whether smoking and short stature in adulthood were independent risk factors for hearing loss. We reanalyzed data from the Danish Work Environment Cohort Study (an existing cohort study), on prevalence of self-reported hearing loss among 7,221 employees and on five-year incidence among 4,610 employees. We found that smoking predicted hearing loss incidence and prevalence. Smoking did not predict incidence at noise exposure during half or more of a worker's hours. Very short stature predicted prevalence in the total adult population only weakly, but strongly among employees born before 1951. These prospective findings indicate that smoking is an independent risk factor for incidence of hearing loss. Very short stature predicted prevalence of hearing loss only in a sub-population.