mmHg Lower Diastolic Blood Pressure Research Articles

Associations between daily home blood pressure measurements and self-reports of lifestyle and symptoms in primary care: the PERHIT study

Objective To explore in a primary care setting the associations between patients’ daily self-measured blood pressure (BP) during eight weeks and concurrent self-reported values of wellbeing, lifestyle, symptoms, and medication intake. We also explore these associations for men and women separately. Design and setting The study is a secondary post-hoc analysis of the randomised controlled trial PERson-centeredness in Hypertension management using Information Technology (PERHIT). The trial was conducted in primary health care in four regions in Southern Sweden. Patients Participants (n = 454) in the intervention group in the PERHIT-trial used an interactive web-based system for self-management of hypertension for eight consecutive weeks. Each evening, participants reported in the system their wellbeing, lifestyle, symptoms, and medication adherence as well as their self-measured BP and heart rate. Main outcome measures Association between self-reported BP and 10 self-report lifestyle-related variables. Results Self-reported less stress and higher wellbeing were similarly associated with BP, with 1.0 mmHg lower systolic BP and 0.6/0.4 mmHg lower diastolic BP (p < 0.001). Adherence to medication had the greatest impact on BP levels (5.2/2.6 mmHg, p < 0.001). Restlessness and headache were also significantly associated with BP, but to a lesser extent. Physical activity was only significantly associated with BP levels for men, but not for women. Conclusion In hypertension management, it may be important to identify patients with high-stress levels and low wellbeing. The association between medication intake and BP was obvious, thus stressing the importance of medication adherence for patients with hypertension.

Associations between major dietary patterns and blood pressure among Southwest Chinese: A cross-sectional analysis based on the China Multi-Ethnic Cohort (CMEC) study

Background and aimsIn the less developed multi-ethnic regions (LEMRs) of Southwest China, the associations between dietary patterns and blood pressure (BP) values remain unclear. We aimed to investigate such associations and related effect modifiers. Methods and resultsThis study included 81,433 participants from the China Multi-Ethnic Cohort Study. Dietary intakes during the year before the interview were measured with the Quantitative Food Frequency Questionnaire. Three major dietary patterns that were highly in line with geographical and ethnic distributions of the study population, i.e., “Sichuan Basin,” “Yunnan-Guizhou Plateau,” and “Qinghai-Tibet Plateau,” were derived using principal component factor analysis. The multilinear regression model combined with inverse probability of exposure weighting was used to estimate the associations between dietary patterns and BP values.Comparing the highest with the lowest quintiles, the Sichuan Basin dietary pattern (characterized by urban lifestyles) was associated with 2.67 mmHg lower systolic blood pressure (SBP) (95% CI: −3.07 to −2.27) and 0.89 mmHg lower diastolic blood pressure (95% CI: −1.12 to −0.65). In contrast, both the Yunnan-Guizhou Plateau (characterized by agricultural lifestyles) and the Qinghai-Tibet Plateau dietary patterns (characterized by nomadic lifestyles) showed positive associations with BP. In the stratified analysis, the associations between dietary patterns and SBP were significantly stronger in women than in men for all three kinds of dietary patterns. ConclusionBoth major dietary patterns and their associations with BP showed a substantial disparity in LEMRs of Southwest China. Dietary patterns in regions of higher socioeconomic status are more conducive to reducing the rising of BP, especially for women and urban residents, which might provide insights into the BP control in LEMRs of Southwest China.

Effect of a sodium restriction diet on albuminuria and blood pressure in diabetic kidney disease patients: a meta-analysis.

A sodium restriction diet is a key component of chronic kidney disease (CKD) management. However, the efficacy of its use in patients with diabetic kidney disease (DKD) is uncertain. The present meta-analysis explored the effects of restricting sodium intake on albuminuria and blood pressure in DKD patients with albuminuria. We searched the Cochrane Central Register of Controlled Trials, Web of Science, MEDLINE, and EMBASE for randomized controlled trials, and we reviewed the references of all searched articles to avoid omitting other relevant articles. Our primary endpoints were blood pressure, albumin excretion rate, and plasma renin activity. We assessed pooled data using a random-effects model. Of the 661 articles identified, a total of 12 articles were included in the meta-analysis. The random-effects model indicated that salt-restriction diet interventions led to a poled - 4.72mmHg (95% CI - 6.71, - 2.73) difference in systolic blood pressure and that the intervention resulted in a 2.33mmHg lower diastolic blood pressure (95% CI - 3.61, - 1.05). In patients with microalbuminuria, restricted sodium intake decreased the albumin excretion rate (AER) by 12.62mg/min (95% CI - 19.64, - 5.60). Furthermore, the AER was 127.69mg/min lower in patients with macroalbuminuria (95% CI - 189.07, - 66.32). Moderate sodium restriction diets reduce urinary albumin excretion and decrease the level of blood pressure, especially for patients with macro-albuminuria. Thus, it is necessary to strengthen the intervention and health education as well as to provide individualized dietary advice.

Vegetable nitrate intake, blood pressure and incident cardiovascular disease: Danish Diet, Cancer, and Health Study

Whether the vascular effects of inorganic nitrate, observed in clinical trials, translate to a reduction in cardiovascular disease (CVD) with habitual dietary nitrate intake in prospective studies warrants investigation. We aimed to determine if vegetable nitrate, the major dietary nitrate source, is associated with lower blood pressure (BP) and lower risk of incident CVD. Among 53,150 participants of the Danish Diet, Cancer, and Health Study, without CVD at baseline, vegetable nitrate intake was assessed using a comprehensive vegetable nitrate database. Hazard ratios (HRs) were calculated using restricted cubic splines based on multivariable-adjusted Cox proportional hazards models. During 23 years of follow-up, 14,088 cases of incident CVD were recorded. Participants in the highest vegetable nitrate intake quintile (median, 141 mg/day) had 2.58 mmHg lower baseline systolic BP (95%CI − 3.12, − 2.05) and 1.38 mmHg lower diastolic BP (95%CI − 1.66, − 1.10), compared with participants in the lowest quintile. Vegetable nitrate intake was inversely associated with CVD plateauing at moderate intakes (~ 60 mg/day); this appeared to be mediated by systolic BP (21.9%). Compared to participants in the lowest intake quintile (median, 23 mg/day), a moderate vegetable nitrate intake (median, 59 mg/day) was associated with 15% lower risk of CVD [HR (95% CI) 0.85 (0.82, 0.89)]. Moderate vegetable nitrate intake was associated with 12%, 15%, 17% and 26% lower risk of ischemic heart disease, heart failure, ischemic stroke and peripheral artery disease hospitalizations respectively. Consumption of at least ~ 60 mg/day of vegetable nitrate (~ 1 cup of green leafy vegetables) may mitigate risk of CVD.

Mendelian randomization analysis does not support causal associations of birth weight with hypertension risk and blood pressure in adulthood.

Epidemiology studies suggested that low birthweight was associated with a higher risk of hypertension in later life. However, little is known about the causality of such associations. In our study, we evaluated the causal association of low birthweight with adulthood hypertension following a standard analytic protocol using the study-level data of 183,433 participants from 60 studies (CHARGE-BIG consortium), as well as that with blood pressure using publicly available summary-level genome-wide association data from EGG consortium of 153,781 participants, ICBP consortium and UK Biobank cohort together of 757,601 participants. We used seven SNPs as the instrumental variable in the study-level analysis and 47 SNPs in the summary-level analysis. In the study-level analyses, decreased birthweight was associated with a higher risk of hypertension in adults (the odds ratio per 1 standard deviation (SD) lower birthweight, 1.22; 95% CI 1.16 to 1.28), while no association was found between genetically instrumented birthweight and hypertension risk (instrumental odds ratio for causal effect per 1 SD lower birthweight, 0.97; 95% CI 0.68 to 1.41). Such results were consistent with that from the summary-level analyses, where the genetically determined low birthweight was not associated with blood pressure measurements either. One SD lower genetically determined birthweight was not associated with systolic blood pressure (β = - 0.76, 95% CI - 2.45 to 1.08mmHg), 0.06mmHg lower diastolic blood pressure (β = - 0.06, 95% CI - 0.93 to 0.87mmHg), or pulse pressure (β = - 0.65, 95% CI - 1.38 to 0.69mmHg, all p > 0.05). Our findings suggest that the inverse association of birthweight with hypertension risk from observational studies was not supported by large Mendelian randomization analyses.

Long-Chain Polyunsaturated Fatty Acids Are Associated with Blood Pressure and Hypertension over 10-Years in Black South African Adults Undergoing Nutritional Transition

Nutritional transition in Africa is linked with increased blood pressure (BP). We examined 10-year fatty acid status and longitudinal associations between individual long-chain polyunsaturated fatty acids (PUFA), BP and status of hypertension (≥140/90 mmHg and/or medication use) in black South Africans. We included 300 adults (>30 years) participating in the Prospective Urban Rural Epidemiology study, and analysed data from three consecutive examinations (2005, 2010 and 2015 study years). Fatty acids in plasma phospholipids were analysed by gas chromatography-mass spectrometry. We applied sequential linear mixed models for continuous outcomes and generalized mixed models for the hypertension outcome, in the complete sample and separately in urban and rural subjects. Mean baseline systolic/diastolic BP was 137/89 mmHg. Ten-year hypertension status increased among rural (48.6% to 68.6%, p = 0.001) and tended to decrease among urban subjects (67.5% to 61.9%, p = 0.253). Regardless of urbanisation, n-6 PUFA increased and eicosapentaenoic acid (EPA, C20:5 n-3) decreased over the 10-years. Subjects in the highest tertile of arachidonic acid (C20:4 n-6) had 3.81 mmHg lower systolic (95% confidence interval (CI): −7.07, −0.54) and 3.82 mmHg lower diastolic BP (DBP) (95% CI: −5.70, −1.95) compared to the reference tertile, irrespective of lifestyle and clinical confounders. Similarly, osbond acid (C22:5 n-6) was inversely associated with DBP. Over the 10-years, subjects in the highest EPA tertile presented with +2.92 and +1.94 mmHg higher SBP and DBP, respectively, and with 1.46 higher odds of being hypertensive. In black South African adults, individual plasma n-6 PUFA were inversely associated with BP, whereas EPA was adversely associated with hypertension, supporting implementation of dietary fat quality in national cardiovascular primary prevention strategies.

Association of blood pressure with estimates of 24-h urinary sodium and potassium excretion from repeated single-spot urine samples.

While the association between 24-h urinary sodium and potassium excretion with blood pressure is well established, the relationships of these ions to spot urine measurements are unclear. Our purpose is to assess the association between blood pressure and the estimated 24-h sodium and potassium excretion from repeated single-spot urine samples. Spot urine and blood pressure were collected annually during a 5-year period from 4360 Japanese workers with ages ranging from 19 to 55 years. Estimates of 24-h sodium and potassium excretion were based on Tanaka's formula. Overall, a single standard deviation increase in the estimated sodium excretion (36.5 mmol/day) was associated with a 1.3 mmHg higher systolic blood pressure and a 0.8 mmHg higher diastolic blood pressure (P < 0.001). A single standard deviation increase in estimated potassium excretion (8.9 mmol/day) was associated with a 1.1 mmHg lower systolic blood pressure and a 0.7 mmHg lower diastolic blood pressure (P < 0.001). As a combined measure of the excretion of both electrolytes, the estimated 24-h sodium-to-potassium ratio was positively associated with both blood pressures (P < 0.001). Associations of blood pressure with sodium and the sodium-to-potassium ratio increased with age and were stronger in men compared to women. Associations with potassium and the sodium-to-potassium ratio were stronger in individuals who were overweight. The findings provide evidence for an association between blood pressure and the estimated 24-h sodium and potassium excretion from repeated single-spot urine samples. As convenient measures of dietary intake for each electrolyte, repeated spot urine samples may be useful for assessing hypertension risk, especially in men, older individuals, and overweight individuals.

Physical activity, sitting, and risk factors of cardiovascular disease: a cross-sectional analysis of the CARRS study.

We aimed to estimate the associations between substituting 30-min/day of walking or moderate-to-vigorous physical activity (MVPA) for 30min/day of sitting and cardiovascular risk factors in a South Asian population free of cardiovascular disease. We collected information regarding sitting and physical activity from a representative sample of 6991 participants aged 20years and above from New Delhi, India and Karachi, Pakistan enrolled in 2010-2011 in the Center for cArdio-metabolic Risk Reduction in South Asia study using the International Physical Activity Questionnaire (short form). We conducted isotemporal substitution analyses using multivariable linear regression models to examine the cross-sectional associations between substituting MVPA and walking for sitting with cardiovascular risk factors. Substituting 30min/day of MVPA for 30min/day of sitting was associated with 0.08mmHg lower diastolic blood pressure (β = -0.08 [- 0.15, - 0.0003]) and 0.13mg/dl higher high-density lipoprotein cholesterol (β = 0.13 [0.04, 0.22]). Substituting 30min/day of walking for 30min/day of sitting was associated with 0.08kg/m2 lower body mass index (β = -0.08 [- 0.15, - 0.02]), and 0.25cm lower waist circumference (β = -0.25 [- 0.39, - 0.11]). In conclusion, substituting time engaged in more-active pursuits for time engaged in less-active pursuits was associated with modest but favorable cardiovascular risk factor improvements among South Asians.

Human Reponses to Biophilic Indoor Environment

Biophilic design, which incorporates natural elements into the built environment, has received increasing attention in both design and health fields. Epidemiological and experimental studies have provided sufficient evidence that contact with outdoor nature has positive impacts on human health and wellbeing. However, the potential for similar health benefits in indoor biophilic environments remains unclear. We designed a randomized crossover study to examine the physiological and cognitive responses to biophilic indoor environments by using virtual reality (VR) and wearable bio-monitoring sensors. In this study, 28 participants spent time in an indoor environment featuring biophilic design elements and one without, with the order of the visit randomized. In each visit, they experienced the same environment for 5-minutes in reality and virtually by using VR. The indoor biophilic environment was associated with a decrease in participants's blood pressure. The overall differential effects for participants experiencing an indoor environment with biophilic elements versus none was 8.56 (95%CI: 5.60-11.52) mmHg lower systolic and 3.57 (95%CI: 0.36-6.78) mmHg lower diastolic blood pressure. In addition, their skin conductance decreased by 0.18 (95%CI: -0.004-0.36) µS and short-term memory improved by 14% (95%CI: 5.3%-23.2%). Moreover, our findings indicate that participants had similar physiological and cognitive benefits in the virtual environment and actual environment. The results indicate that biophilic environment may be benefitial in reduce stress in indoor settings. Additionally, the parity in results in virtual and real environments provides evidence that using VR can be an effective tool to simulate visual exposures when access to the real environment is not feasible.

Abstract P224: Urinary Excretion of Sodium, Potassium, Calcium and Magnesium and Blood Pressure Among a Population of ≥ 20-Year-Olds: Evidence From Southwest Coastal Bangladesh

We analyzed data from a stepped wedge randomized trial to evaluate how urinary Na, K, Ca and Mg excretion are associated with the change in blood pressure (BP) among the adult population. We followed up a cohort of 1,191 participants (&gt;20 years old) from 540 households in 16 communities of southwest coastal Bangladesh for five visits during December 2016 - April 2017 when they were exposed to high salinity drinking water. In all visits, we measured participants’ BP (N=5,746) and 24-hour urinary Na, K, Ca and Mg. We used multilevel linear regression models to determine the association among change in urinary excretion of Na, K, Ca and Mg with differences in mean systolic blood pressure (SBP) and diastolic blood pressure (DBP). Models included participant-, household-, and community-level random intercepts and were adjusted for age, sex, BMI, physical activity, smoking status, and household wealth. We restricted analysis among participants who had complete 24-hour urine collection based on measured versus expected urinary creatinine ratio of &gt;=0.7 (N=5,103). The median urinary 24 hours Na excretion was 164 mmol, K was 34 mmol, Ca was 126 mg, and Mg was 83 mg in visit 1. The mean population SBP was 115.6 mmHg in visit 1 and 110.2 in visit 5, and the mean DBP was 68.9 mmHg in visit 1 and 65.9 in visit 5. Compared to visit 1, we found 85% higher urinary Ca in visit 3 and 57% higher urinary Mg in visit 5. We found 100 mmol per 24 hours increase in urinary Na was associated with 1.74 (95% CI: 0.85, 2.62) mmHg higher SBP and 0.51 (95% CI: -0.06, 1.08) mmHg higher DBP, and 50 mmol per 24 hours increase in urinary K was associated with 2.39 (95% CI: 0.84, 3.94) mmHg lower SBP and 0.79 (95% CI: -1.76, 0.17) mmHg lower DBP. We found 100 mg per 24 hours increase in urinary Ca was associated with 0.29 (95% CI: 0.02, 0.60) mmHg lower SBP and 0.32 (0.07, 0.57) mmHg lower DBP, and 100 mg per 24 hours increase in urinary Mg was associated with 1.09 (95% CI: 0.55, 1.64) mmHg lower SBP and 0.41 (0.07, 0.76) mmHg lower DBP. We found SBP lowering effect of urinary Mg increased if urinary Ca was lower (p = 0.048). We found urinary K, Ca, and Mg are associated with lower BP in coastal Bangladesh. Our results suggest a high intake of these beneficial minerals alongside Na reduction may successfully lower mean BP of the population.

Physiological and cognitive performance of exposure to biophilic indoor environment

Biophilic design, which incorporates natural elements into the built environment, has received increasing attention in both the design and health fields. But research quantifying physiological and cognitive benefits of indoor biophilic features is sparse. This randomized crossover study examines the physiological and cognitive responses to natural elements in an office building. Twenty-eight participants spent time in an indoor environment featuring biophilic design elements and one without, with the order of the visit randomized. In each visit, they experienced the environment for 5-min in reality and virtually by using virtual reality (VR). Wearable sensors were used to measure blood pressure, galvanic skin response and heart rate. Cognitive tests were administrated after each exposure. The indoor biophilic environment was associated with a decrease in participants' blood pressure. The overall differential effects for participants experiencing an indoor environment with biophilic elements versus none was 8.6 mmHg lower systolic and 3.6 mmHg lower diastolic blood pressure. In addition, their skin conductance decreased 0.18 μS greater than when they experienced the non-biophilic setting. Short-term memory improved by 14%. Participants reported a decrease in negative emotions and an increase in positive emotions after experiencing the biophilic setting. Moreover, our findings indicate that participants experiencing biophilic environment virtually had similar physiological and cognitive responses as when experiencing the actual environment. This gives rise to the possibility of reducing stress and improving cognition by using virtual reality to provide exposures to natural elements in a variety of indoor settings where access to nature may not be possible.

Association between HIV and blood pressure in adults and role of body weight as a mediator: Cross-sectional study in Uganda.

The authors sought to describe the association between human immunodeficiency virus (HIV) and blood pressure (BP) levels, and determined the extent to which this relationship is mediated by body weight in a cross-sectional study of HIV-infected and HIV-uninfected controls matched by age, sex, and neighborhood. Mixed-effects models were fit to determine the association between HIV and BP and amount of effect of HIV on BP mediated through body mass index. Data were analyzed from 577 HIV-infected and 538 matched HIV-uninfected participants. HIV infection was associated with 3.3mmHg lower systolic BP (1.2-5.3mmHg), 1.5mmHg lower diastolic BP (0.2-2.9mmHg), 0.3m/s lower pulse wave velocity (0.1-0.4mmHg), and 30% lower odds of hypertension (10%-50%). Body mass index mediated 25% of the association between HIV and systolic BP. HIV infection was inversely associated with systolic BP, diastolic BP, and pulse wave velocity. Comprehensive community-based programs to routinely screen for cardiovascular risk factors irrespective of HIV status should be operationalized in HIV-endemic countries.

Seasonal and Diurnal Variations in Cardiometabolic Traits in the GOLDN Study

Seasonal and diurnal variations in cardiometabolic traits are driven by changes in photoperiod and outdoor temperature and also the circadian clock. Because participant recruitment in the multi‐sited family‐based Genetics of Lipid Lowering Drugs and Diet Network (GOLDN) cohort was evenly distributed over a 3‐year period and ranged between 7:00 AM and 11:00 AM, we had the opportunity to examine whether photoperiod and outdoor temperature on the day of participants' assessment and time of assessment associate with cardiometabolic traits. We used multiple linear regression models adjusted for age, sex, BMI and study site (n =821). Outdoor temperature showed associations with blood pressure (BP) independent of photoperiod. Each additional 1oC increase was associated with 0.19 mmHg lower systolic BP [β ± SE = ‐0.19 ± 0.05 mmHg; P =0.0002] and 0.10 mmHg lower diastolic BP [β ± SE = ‐0.10 ± 0.03 mmHg; P =0.001]. The association between outdoor temperature and BP was modified by age and hypertension status, but not geographical location. No seasonal differences were observed in self‐reported dietary intake, and anthropometric, lipid and glycemic traits. Furthermore, assessment time showed associations with fasting lipids [total cholesterol (P =3.3E‐06), LDL‐C (P =0.004), and TG (P =0.004)] and postprandial response to a high‐fat meal (P =1.1E‐07). The observed associations lend support to the oscillation of important cardiometabolic traits, and suggest that cross‐sectional analyses of population‐based cohorts may need to factor in seasonality and assessment time when investigating cardiometabolic traits, particularly BP.

Sustained use of biogas fuel and blood pressure among women in rural Nepal

BackgroundMore than two fifths of the world's population cook with solid fuels and are exposed to household air pollution (HAP). As of now, no studies have assessed whether switching to alternative fuels like biogas could impact cardiovascular health among cooks previously exposed to solid fuel use. MethodsWe conducted a propensity score matched cross-sectional study to explore if the sustained use of biogas fuel for at least ten years impacts blood pressure among adult female cooks of rural Nepal. We recruited one primary cook ≥30 years of age from each biogas (219 cooks) and firewood (300 cooks) using household and measured their systolic (SBP) and diastolic blood pressure (DBP). Household characteristics, kitchen ventilation and 24-h kitchen carbon monoxide were assessed. We matched cooks by age, body mass index and socio-economic status score using propensity scores and investigated the effect of biogas use through multivariate regression models in two age groups, 30–50 years and >50 years to account for any post-menopausal changes. ResultsWe found substantially reduced 24-h kitchen carbon monoxide levels among biogas-using households. After matching and adjustment for smoking, kitchen characteristics, ventilation status and additional fuel use, the use of biogas was associated with 9.8mmHg lower SBP [95% confidence interval (CI), −20.4 to 0.8] and 6.5mmHg lower DBP (95% CI, −12.2 to −0.8) compared to firewood users among women >50 years of age. In this age group, biogas use was also associated with 68% reduced odds [Odds ratio 0.32 (95% CI, 0.14 to 0.71)] of developing hypertension. These effects, however, were not identified in younger women aged 30–50 years. ConclusionsSustained use of biogas for cooking may protect against cardiovascular disease by lowering the risk of high blood pressure, especially DBP, among older female cooks. These findings need to be confirmed in longitudinal or experimental studies.

Abstract MP03: Associations Of 24-hour Blood Pressure Patterns With Cognitive Function In Healthy Older Adults

Background: Abnormal 24-hour ambulatory blood pressure monitoring (ABPM) patterns have been associated with diminished cognitive function in hypertensive and very elderly populations. The relationship between ABPM patterns in community-living older adults is unknown. Methods: We conducted a cross-sectional study in which ABPM, in-clinic blood pressure, and cognitive function measures were obtained in 354 community living older adults. We used multiple linear regression to examine the associations of in-clinic and ABPM with the Montreal Cognitive Assessment (MoCA [range 0-30 with lower levels indicating worse cognition]), adjusting for age, sex, race/ethnicity, education, and comorbid medical conditions. Results: The mean age was 72 years, 68% were female, and 13% were African American; 45% had a diagnosis of hypertension. In-clinic blood pressure measurements were not significantly associated with cognitive function after adjustment. In contrast, less nighttime systolic dipping percentage (Figure) and lower 24-hour average diastolic blood pressure obtained from the ABPM were both significantly associated with worse cognitive function. In the final model, each 1% less night-time dipping was associated with 0.25 points (0.1-0.9) lower MoCA score, whereas each 10 mmHg lower diastolic blood pressure was associated with 0.59 (0.14-1.05) points lower MoCA score. Conclusions: In community-living older persons, less nighttime systolic dipping and lower 24-hour diastolic blood pressure obtained by ABPM were associated with worse cognitive function whereas clinic based blood pressure measurements were not. Future studies should examine whether 24-hour diastolic blood pressure and nighttime systolic dipping may predict future risk for cognitive impairment. (Legend: Dipping quartiles: Q1 -17.8% to 6.0%; Q2 6.1% to 11.0%; Q3 11.1% to 16.3%; Q4 16.4% to 34.2%)

Light-Intensity Physical Activity and Cardiometabolic Biomarkers in US Adolescents

BackgroundThe minimal physical activity intensity that would confer health benefits among adolescents is unknown. The purpose of this study was to examine the associations of accelerometer-derived light-intensity (split into low and high) physical activity, and moderate- to vigorous-intensity physical activity with cardiometabolic biomarkers in a large population-based sample.MethodsThe study is based on 1,731 adolescents, aged 12–19 years from the 2003/04 and 2005/06 National Health and Nutrition Examination Survey. Low light-intensity activity (100–799 counts/min), high light-intensity activity (800 counts/min to <4 METs) and moderate- to vigorous-intensity activity (≥4 METs, Freedson age-specific equation) were accelerometer-derived. Cardiometabolic biomarkers, including waist circumference, systolic blood pressure, diastolic blood pressure, HDL-cholesterol, and C-reactive protein were measured. Triglycerides, LDL- cholesterol, insulin, glucose, and homeostatic model assessments of β-cell function (HOMA-%B) and insulin sensitivity (HOMA-%S) were also measured in a fasting sub-sample (n = 807).ResultsAdjusted for confounders, each additional hour/day of low light-intensity activity was associated with 0.59 (95% CI: 1.18–0.01) mmHG lower diastolic blood pressure. Each additional hour/day of high light-intensity activity was associated with 1.67 (2.94–0.39) mmHG lower diastolic blood pressure and 0.04 (0.001–0.07) mmol/L higher HDL-cholesterol. Each additional hour/day of moderate- to vigorous-intensity activity was associated with 3.54 (5.73–1.35) mmHG lower systolic blood pressure, 5.49 (1.11–9.77)% lower waist circumference, 25.87 (6.08–49.34)% lower insulin, and 16.18 (4.92–28.53)% higher HOMA-%S.ConclusionsTime spent in low light-intensity physical activity and high light-intensity physical activity had some favorable associations with biomarkers. Consistent with current physical activity recommendations for adolescents, moderate- to vigorous-intensity activity had favorable associations with many cardiometabolic biomarkers. While increasing MVPA should still be a public health priority, further studies are needed to identify dose-response relationships for light-intensity activity thresholds to inform future recommendations and interventions for adolescents.

1430 – Dementia and lower blood pressure in seven low and middle income countries: the 10/66 cross-sectional surveys

Introduction A relative decline in systolic blood pressure has been found to occur prior to and around the clinical onset of dementia but the reasons for this remain unclear. Aims and objectives In a large series of surveys carried out using identical methodology in populations with relatively low mean blood pressures we investigated the consistency of the association between dementia, dementia severity and resting blood pressure. Methods The analysed sample comprised 15,022 participants from eleven cross-sectional surveys carried out in seven low and middle income countries (Cuba, Dominican Republic, Peru, Venezuela, Mexico, China and India). Associations between dementia status (ascertained through a detailed assessment with extensive cross-cultural validation) and resting blood pressure were described for each sample and then compared in meta-analyses. Results In age- and sex-adjusted linear regression analyses, there was a high level of between-site heterogeneity in these associations (I-squared 60.2% for dementia and SBP). The only site with significant and consistent associations was Cuba (n=2944), the sample with highest mean systolic blood pressure, where dementia was associated with 7.9mmHg lower systolic blood pressure (95% CI 4.7-11.1) and 2.6mmHg lower diastolic blood pressure (95% CI 0.9-4.2). In general, associations between dementia and lower blood pressure were weak or absent in these surveys. Conclusions The association between dementia and low blood pressure, generally observed in Western settings was not observed in these populations with lower hypertension prevalence. These findings do not support a hypothesis that lower blood pressure in dementia is purely secondary to underlying neurodegeneration.

Vitamin C in plasma is inversely related to blood pressure and change in blood pressure during the previous year in young Black and White women

BackgroundThe prevalence of hypertension and its contribution to cardiovascular disease risk makes it imperative to identify factors that may help prevent this disorder. Extensive biological and biochemical data suggest that plasma ascorbic acid may be such a factor. In this study we examined the association between plasma ascorbic acid concentration and blood pressure (BP) in young-adult women.MethodsParticipants were 242 Black and White women aged 18–21 yr from the Richmond, CA, cohort of the National Heart, Lung and Blood Institute Growth and Health Study. We examined the associations of plasma ascorbic acid with BP at follow-up year 10, and with change in BP during the previous year.ResultsIn cross-sectional analysis, plasma ascorbic acid at year 10 was inversely associated with systolic BP and diastolic BP after adjusting for race, body mass index, education, and dietary intake of fat and sodium. Persons in the highest one-fourth of the plasma ascorbic acid distribution had 4.66 mmHg lower systolic BP (95% CI 1.10 to 8.22 mmHg, p = 0.005) and 6.04 mmHg lower diastolic BP (95% CI 2.70 to 9.38 mmHg, p = 0.0002) than those in the lowest one-fourth of the distribution. In analysis of the change in BP, plasma ascorbic acid was also inversely associated with change in systolic BP and diastolic BP during the previous year. While diastolic blood pressure among persons in the lowest quartile of plasma ascorbic acid increased by 5.97 mmHg (95% CI 3.82 to 8.13 mmHg) from year 9 to year 10, those in the highest quartile of plasma vitamin C increased by only 0.23 mmHg (95% CI -1.90 to +2.36 mmHg) (test for linear trend: p < 0.0001). A similar effect was seen for change in systolic BP, p = 0.005.ConclusionPlasma ascorbic acid was found to be inversely associated with BP and change in BP during the prior year. The findings suggest the possibility that vitamin C may influence BP in healthy young adults. Since lower BP in young adulthood may lead to lower BP and decreased incidence of age-associated vascular events in older adults, further investigation of treatment effects of vitamin C on BP regulation in young adults is warranted.

Blood pressure and hypertension in an American colony (Puerto Rico) and on the USA mainland compared, 1886–1930

We compare blood pressure and hypertension between adult men on the USA mainland and in Puerto Rico born during 1886–1930 to test hypotheses about the link between cardiovascular health and large socioeconomic and political changes in society: (a) 8853 men surveyed in Puerto Rico in 1965 and (b) 1449 non-Hispanic White men surveyed on the mainland during 1971–1975. Systolic and diastolic blood pressure and hypertension were regressed separately on demographic and socioeconomic variables and cardiovascular risk factors. Mainland men not taking anti-hypertensive medication showed statistically significant improvements in systolic blood pressure and hypertension at the beginning of the century and men in Puerto Rico showed improvements in diastolic blood pressure but only during the last two quinquenniums. An average man born on the mainland during the last birth quinquennium (1926–1930) had 7.4–8.7 mmHg lower systolic blood pressure and was 61% less likely to have systolic hypertension than one born before 1901. On average Puerto Rican men born during 1921–1925 had ∼1.7 mmHg lower diastolic blood pressure than men born before 1901. Analyses of secular trends in cardiovascular health complements analyses of secular trends in anthropometric indicators and together provide a fuller view of the changing health status of a population.

Birthweight and arterial stiffness and blood pressure in adulthood--results from the Amsterdam Growth and Health Longitudinal Study.

The association between low birthweight and increased blood pressure in later life has repeatedly been confirmed. Increased arterial stiffness may be an underlying mechanism for this phenomenon. This study investigated whether birthweight was related to blood pressure and local and regional arterial stiffness. In 281 subjects (161 women), with a mean age of 36, blood pressure was measured. The diameter, distension, and local pulse pressure of three large arteries were measured simultaneously using ultrasound imaging. Local and regional arterial compliance and distensibility were calculated. Information on birthweight was retrieved with a questionnaire. Linear regression analyses showed a 3.3 mmHg lower systolic blood pressure (SBP) and a 1.8 mmHg lower diastolic blood pressure (DBP), per 1kg higher birthweight. These associations were statistically significant after adjustment for adult weight. Birthweight was significantly and positively related to carotid arterial compliance (P = 0.050), but less so to brachial (P = 0.114) and femoral arterial compliance (P = 0.058). However, after adjustment for adult height, the strength of these associations decreased. Birthweight was not related to arterial distensibility. The association between birthweight and arterial compliance could only partly explain the association between birthweight and blood pressure. Lower birthweight is related to increased blood pressure, and increased arterial stiffness. However, the latter relationship can only partly explain the association between birthweight and blood pressure. Therefore, mechanisms other than arterial stiffness contribute to the birthweight-blood pressure relationship.