The "Learning" Birth Cohort: A New Approach to Catalyze Preventative Psychiatry.

Evaluation of sexual behaviors is essential to better understand the epidemiology of sexually transmitted infections and their sequelae. The National Health and Nutrition Examination Surveys (NHANES) is an ongoing probability sample survey of the US population. Using NHANES sexual behavior data from 1999 to 2012, we performed the following: (1) trend analyses among adults aged 25 to 59 years by 10-year birth cohorts and (2) descriptive analyses among participants aged 14 to 24 years. Sex was defined as vaginal, anal, or oral sex. Among adults aged 25 to 59 years, median age at sexual initiation decreased between the 1940-1949 and 1980-1989 cohorts from 17.9 to 16.2 among females (P trend < 0.001) and from 17.1 to 16.1 among males (P trend < 0.001). Median lifetime partners increased between the 1940-1949 and 1970-1979 cohorts, from 2.6 to 5.3 among females (P trend < 0.001) and from 6.7 to 8.8 among males (P trend < 0.001). The percentage of females reporting ever having a same-sex partner increased from 5.2% to 9.3% between the 1940-1949 and 1970-1979 cohorts (P trend < 0.001). Among participants aged 14 to 24 years, the percentage having had sex increased with age, from 12.5% among females and 13.1% among males at age 14 years to more than 75% at age 19 years for both sexes. Among sexually experienced 14- to 19-year-olds, 45.2% of females and 55.0% of males had at least 3 lifetime partners; 39.4% of females and 48.6% of males had at least 2 partners in the past year. The proportion of females aged 20 to 24 years who reported ever having a same-sex partner was 14.9%. The proportion of participants aged 14-19 or 20-24 years reporting ever having sex did not differ by survey year from 1999 to 2012 for either males or females. Sexual behaviors changed with successive birth cohorts, with more pronounced changes among females. A substantial proportion of adolescents are sexually active and have multiple partners. These data reinforce existing recommendations for sexual health education and sexually transmitted infection prevention targeting adolescents before sexual debut.

Prenatal environment plays an important role in child development and health. Previous research particularly focused on the impact of prenatal stress on offspring outcomes, reporting lifelong changes from birth to adulthood. The aim of this chapter is to provide an overview of this impact together with the underlying physiological and epigenetic mechanisms. Through this overview, I emphasize the importance of establishing prospective birth cohorts to advance our understanding of these mechanisms. As an example of such a cohort, I then introduce the Bogazici Mother Baby Relationship Project (BABIP) birth cohort from Turkey. Considering the significant and long-term effects of the prenatal environment, the findings from such cohorts around the world is crucial for the progress in prevention, intervention and public education programs as well as establishing social policies that would foster better prenatal health and child development.KeywordsPrenatal environmentPrenatal stressChild developmentMaternal physiologyEpigenetics

A healthy working life is fundamental for individuals and society. To date, increasingly research connects the earlier, pre-working life to later working life experiences and beyond, recognizing that a worker’s health and exposure starts before the working life begins. The research, however, often lacks a fundamental understanding of (i) the underlying mechanisms and pathways accounting for differences in different life stages and (ii) the role of the social environment in shaping working life experiences. By integrating a life course perspective in our research and crossing disciplinary borders in rigorous, collaborative research, we may get a better understanding of the complex and dynamic interplay between work, environment and health. A life course perspective for work environment and health research A life course perspective in work environment and health research emphasizes the importance of prior life experiences, including the environments in which individuals were raised and exposed, their familial and educational backgrounds, and their physical and mental health status before entering the workforce (1, 2). Life course research in different disciplines has been instrumental in developing more robust causal models (3, 4), particularly for understanding developmental health trajectories and socioeconomic health inequalities (eg, 5–7). Adopting an interdisciplinary life course perspective in work environment and health research helps researchers answering questions as to whether and how the timing, duration, intensity, and context of past and present exposures (ie, pre-working, working, and non-working exposures) are associated with later life work and health outcomes. For instance, the ‘exposome paradigm’ is a concept used to describe the sum of occupational and environmental exposures an individual encounters throughout life, and how these exposures impact biology and health (8). In exposome research, a broad range of genetic, biological, chemical, physical, social and lifestyle factors is examined throughout the life course to provide a comprehensive picture of potential risk factors impacting working life health (9). In exposome research and beyond, it is important to examine how the exposure-outcome relationships are shaped by specific social, cultural and historical contexts (2). The conceptual framework of the ‘Social Exposome’ may help to integrate the social environment in conjunction with the physical environment into the exposome concept (10). Moreover, focusing on both historical and contemporary contexts is essential not only for advancing research but also for informing policy and practice, for example by identifying entry points for interventions. Exposures during the life course During the individual’s life course, several vulnerable time windows for the impact of a multitude of exposures that potentially harm, protect or promote health, eg, occupational, environmental and social, can be distinguished. The (combinations of) exposures may operate in different life stages and contexts and – directly or indirectly via intergenerational transmission – contribute to health (figure 1). The individual may be particulary sensitive to harmful exposures or adverse experiences during developmental life stages, ie, pre/perinatal, childhood, adolescence, pregnancy and menopause/andropause. Other life stages may reflect vulnerable time windows due to a clustering of exposures, eg, work and family demands during parenthood, or an accumulation of exposures during the (working) life course at retirement and post-retirement age. As illustrated in figure 1, occupational exposure(s) can be divided in exposure through the parents’ exposure (early in life) and an individuals’ own exposure (later in life). Already in the pre/perinatal life stage, occupational exposure starts through the intergenerational transmission of the parents’ occupational exposures. Current and bioaccumulated occupational exposure of chemicals and particles in the father at the time of conception can affect sperm quality. Together with the mother’s exposure to occupational exposures of chemicals and particles prior to conception – or chemicals, particles, physical factors, ergonomic load, organizational and (psycho-)social conditions at work during pregnancy – this may affect fetal development and later disease development during the child’s life course (11–15). During childhood, the growing child is exposed to parental occupational exposure(s), directly through chemicals and particles in the work clothes and skin or indirectly through organizational and psychosocial factors in the work environment that may increase the risk for mental and physical health problems in parents, which in turn may affect their parental rearing quality (16, 17). During adolescence and early adulthood, individuals usually encounter their first direct occupational exposures through their first (student) job or jobs. Already from this life stage, occupational exposures may accumulate during the (working) life course and may affect not only the active working life but also the post working life. Also important to note is that brain plasticity is not limited to childhood, adolescence or young adulthood as it persists throughout life. Some studies indicate that high physical and chemical exposure during this life stage, can increase the risk of disease later in life (18). A poor psychosocial school or work environment in younger years may also increase the risk of adverse labour market outcomes and mental health problems later in life (19, 20). In adulthood, men and women often start with (the planning of) family formation. Some occupational exposures affect fecundability, others can increase the risk of pregnancy-related disease, such as preeclampsia, hypertension or diabetes, or affect the offspring (21, 22). Chemicals, heat and stress-related exposures affect the ability to conceive. During pregnancy, the bodily and mental systems are vulnerable with changes in the endocrine and inflammation response that can dysregulate the HPA-axis, resulting in a prolonged stress response. The placenta can filter out many hazards, but not all toxicants, such as methylmercury and arsenic (23, 24). Physical exposure, such as noise and vibration, but also shift and night work can affect the womb and cause fetal growth restriction, preterm birth, and hearing impairment (eg, 12, 13, 25–27). During parenthood, occupational exposures may affect the parents’ (mental) health and work-family balance (28, 29). Many chemical and physical exposures have now manifested in disease, eg, allergy, asthma and musculoskeletal diseases (28). During menopause in women, with a drastic decrease in oestrogen, and the slow testosterone decline in men (sometimes referred to as andropause), dysregulations of the hormone system may disrupt and affect the individual’s susceptibility for occupational exposures in a way similar to environmental exposures (30). Towards retirement, the total cumulative occupational exposure burden over the working life course and the current exposure will affect the ability to stay at work and in the labor market. Post retirement, most direct occupational exposures have ceased, but others may have (bio-) accumulated over time and may cause health problems that manifest after retirement (31, 32). Along with occupational exposures, a multitude of other exposures are present during the entire life course that may operate across different contexts to contribute to health (see figure 1). For instance, chemical, physical and social stressors during the life course leave traces (‘memories’) on the molecular and tissue levels that may affect later life health (33). Epigenetic marks act as heritable memories in the cell as they respond to different endogenous and exogenous signals and can be propagated from one generation of cells to the next generation of cells (33). Next to the epigenetic marks, the social environment and social determinants of health during the life course, eg, socio-economic and lifestyle factors, social relationships, social cohesion and support, are known to impact health and add to the multitude of exposures to be examined, among others in conjunction with the environmental exposome (eg, 34). In residential, family and school contexts, exposures such as air pollution, drinking water pollution, noise, artificial light at night, limited access to green space and crowding may play a role, as can adverse childhood experiences (eg, 35, 36). Moreover, on the overarching societal context, legislations, labor market conditions, norms, values and cultural aspects may affect worker health (2, 37). Main knowledge gaps and challenges Both conceptual and empirical challenges have to be tackled when conducting work environment and health research with an interdisciplinary life course perspective. On the conceptual level, different paradigms and nomenclature still exist in the various disciplines examining the impact of (occupational) exposures on later life health outcomes, which contributes to fragmented research and publication thereof in specialized journals. On the empirical level, questions arise such as: Is it feasible to examine mechanisms and pathways across different exposure levels considering a life course perspective? Is the follow-up duration of existing birth and other cohorts sufficient to address the dynamic interplay between the work environment and health? Are the multifaceted, constantly changing contexts captured? Effect sizes are often small on an individual level and statistical power decreases when several rare assumptions have to be fulfilled to examine clusters or combinations of exposures and contexts in relation to health outcomes. Big data, interdisciplinary research protocols and innovative, advanced statistical models to capture the life course perspective are needed to proceed beyond the exposome studies that are currently being finalized within the EU Horizon 2020 exposome call (https://www.humanexposome.eu). Moreover, a better understanding is needed of how occupational, environmental and social exposures affect individuals (i) in vulnerable time windows, eg, do exposures contribute to health advantages and/or disadvantages, and (ii) while transitioning between and within different life stages (38). Studies in different disciplines have focused on the childhood and retirement life stages, see eg, the research on the school-to-work transition or the work-to-retirement transition (39–41), but little is known about the menopause or andropause life stage. Last, rigorous examinations of different lifecourse models (eg, sensitive periods) and exposure models (eg, current, first, last, peak, single, chronic or accumulated), and their impact on health are needed within and across the different vulnerable time windows and life stages as exposure-outcome relationships may differ and thus call for targeted (preventive) policies and practices (42–44). Interdisciplinary research opportunities The challenges towards a better understanding of the complex and dynamic interplay between the work environment and health provide ample opportunities for rigorous, collaborative quantitative and in-depth qualitative life course research across different research strands. Researchers from different disciplines, such as occupational and environmental medicine, epidemiology, toxicology, health science, sociology, psychology, demography, public (mental) health, and genetics to name a few, should not shy away from the complexity, but embrace the opportunity to use their knowledge and skills to collectively address relevant research questions. Interdisciplinary research opportunities are already present today and will emerge even more in the years to come as more cohorts designed as birth cohorts or multi-generational cohorts mature (eg, LifelinesNext, 45). Researchers have or get access to (national) registers, databases with individual-level internal and external exposure information and neighbourhood-level exposure information or linkages of all these exposure and health data, allowing them to examine the impact of exposures in advanced causal models on later life health. To illustrate the value of and research opportunities with existing data, Ubalde-Lopez and colleagues (46) recently argued that parental work-related data collected in birth cohorts is a valuable yet underutilized resource that could be exploited more fruitfully in the collaboration between birth cohort research, occupational epidemiology and sociology. Having said that, the authors also refer to the possible constraints of eg, cross-national comparative research in terms of technical (ie, harmonization) and ethical challenges (46). In conclusion, to move research on the work environment and health forward, we call for a more integrated, interdisciplinary approach that considers the timing and accumulation of occupational, environmental and social exposures over the life course.

The incidence of breast cancer among South Korean women, a historically low-risk population, has increased over the past 3 decades, with marked changes in socioeconomic environment by birth cohort. We investigated associations between breast cancer risk and reproductive factors as well as the impact of birth cohort in those associations. This was a cross-sectional study of data from the Korea National Health and Nutrition Examination Survey for 2013-2016. Data from 10 012 parous women 30 years or older were analyzed using descriptive statistics and Cox multivariate regression after adjusting for socioeconomic status, educational level, occupation, and birth cohort. Of the reproductive factors considered-age at menarche, number of pregnancies, age at first birth, age at last birth, breastfeeding duration, and use of oral contraceptives-only age at menarche was associated with breast cancer risk. Higher educational level, not having an occupation, and younger birth cohort were also associated with increased risk of breast cancer, with birth cohort the strongest of these impact factors. Whereas the relationship between reproductive factors and breast cancer risk was relatively weak, birth cohort was the most important risk factor for breast cancer. The results provide a basis and a rationale for developing birth cohort-based clinical guidelines for breast cancer prevention and early detection, treatment, and survivorship. These findings should also be useful to researchers in other countries experiencing rapid changes in breast cancer incidence.

Allergy-related outcomes at 12 months in the CORAL birth cohort of Irish children born during the first COVID 19 lockdown.

The aim of our study was to quantify sex-specific patterns of smoking prevalence and initiation in 10-year birth cohorts from 1910 to 1989 in Australia. We combined individual data of 385,810 participants from 33 cross-sectional surveys conducted between 1962 and 2018. We found that age-specific smoking prevalence varied considerably between men and women within birth cohorts born before 1960. The largest difference was observed in the earliest cohort (1910–1919), with up to 37.7% point greater proportion of current smokers in men than in women. In subsequent cohorts, the proportion decreased among men, but increased among women, until there was no more than 7.4% point difference in the 1960–69 birth cohort. In the 1970–79 and 1980–89 cohorts, smoking among men marginally increased, but the proportion was at most ~11.0% points higher than women. Our analysis of initiation indicated that many women born before the 1930s who smoked commenced smoking after age 25 years (e.g., ~27% born in 1910–19); compared to at most 8% of men in any birth cohort. The earliest birth cohort (1910–1919) had the greatest difference in age at initiation between sexes; 26.6 years in women versus 19.0 in men. In later cohorts, male and female smokers initiated increasingly earlier, converging in the 1960–69 cohort (17.6 and 17.8 years, respectively). While 22.9% of men and 8.4% of women initiated smoking aged < = 15 in the 1910–1919 cohort, in the latest cohort (1980–89) the reverse was true (21.4% and 28.8% for men and women, respectively). Marked differences in smoking prevalence and age at initiation existed between birth cohorts of Australian men and women born before 1960; after this, sex-specific trends in prevalence and initiation were similar. Understanding these patterns may inform the evaluation of tobacco control policies and the targeting of potential interventions for exposed populations such as lung cancer screening.

Translational opportunities in the prenatal immune environment: Promises and limitations of the maternal immune activation model

Understanding why inequalities in alcohol-related mortality trends by sex and country exist is essential for developing health policies. Birth cohort effects, indicative of differences by generation in drinking, have rarely been studied. This study estimated the relative contributions of birth cohorts to liver cirrhosis mortality trends and compared sex- and country-specific cohort patterns across eight European countries. Time-series analysis of population-level mortality data. Austria, Finland, Hungary, Italy, the Netherlands, Poland, Spain and Sweden; 1950-2011. National populations aged 15-94years. We modelled country- and sex-specific liver cirrhosis mortality (from national vital registers) adjusting for age, period and birth cohort. Birth cohorts (adjusted for age and period) made statistically significant contributions to liver cirrhosis mortality in all countries and for both sexes (P<0.001), and more so among women (average contribution to deviance reduction of 38.8%) than among men (17.4%). The observed cohort patterns were statistically different between all but two country pairs (P<0.001). Sex differences existed overall (P<0.001), but not in the majority of countries (P>0.999). Visual inspection of birth cohort patterns reveals birth cohorts at higher risk of liver cirrhosis mortality. The inclusion of the birth cohort dimension improves the understanding of alcohol-attributable mortality trends in Europe. Birth cohorts at higher risk of liver cirrhosis mortality were born during 1935-49 in Sweden and Finland, around 1950 in Austria and the Netherlands and 1960 or later in Hungary, Italy, Poland and Spain.

Little is known about whether large-scale environmental changes, such as those seen with urbanization, are differentially associated with SBP versus DBP, and whether those changes vary by birth cohort. We used data from the China Health and Nutrition Survey, a population-based cohort study of Chinese adults (n = 18 754 aged 18-70 years), seen a maximum of seven times from 1991 to 2009. We used hierarchical multivariable linear models to simultaneously estimate SBP and DBP as correlated outcomes over time, accounting for their physiologic, time-varying correlation. Main exposure variables were urbanicity, age, and birth cohort. Over 18 years of modernization, median SBP and DBP increased by 10 and 7 mmHg, respectively. Our hierarchical model results suggest greater temporal increases in SBP and particularly DBP at lower versus higher urbanicity. At the same chronological age, for a 10-year difference in birth cohort (i.e. born in 1980s versus 1970s), the adjusted mean DBP was approximately 3 mmHg higher for the later birth cohort (P < 0.001). Pulse pressure (calculated as model-predicted SBP minus DBP) was also higher at low versus high urbanicity. These results suggest increased susceptibility of DBP (and thus peripheral vascular resistance) to environmental change, particularly in younger Chinese adults. Because DBP more strongly predicts cardiovascular disease risk in younger adulthood, hypertension-related health burden in China may increase over time.

Intergenerational Impact of Maternal Early Life Stress on Infant Development: Risk and Protective Factors From the BABIP Birth Cohort

Covariation between glucocorticoid levels and receptor expression modulates embryo development and postnatal phenotypes in gulls

A Blueprint for Genetic Determinism

People in Sweden have internationally good health, work environment and quality of life, a picture that has lately been questioned because of the sharp increase in stress-related diagnoses, especially among young women. This study aims to better understand how stress and psychosocial work stressors vary across age and birth cohorts using data collected between 2008 and 2018. Using hierarchical age-period-cohort-growth curve models and data from the Swedish Longitudinal Occupational Survey of Health, we estimated the age trajectories of job demands, job control, perceived long-lasting stress, sustained emotional stress and self-rated health by birth cohort. Separate analyses by sex and occupational status were also conducted. Job demands, perceived long-lasting stress and sustained emotional stress decreased with age, while self-rated health deteriorated. Statistically significant cohort and age × cohort interactions suggest that more recent birth cohorts have both a) higher job demands, lower job control, more sustained emotional stress and worse self-rated health, and b) a less favourable development with age for all outcomes. However, these cohort differences are primarily driven by younger cohorts, and they are less pronounced or inconsistent among older cohorts. Occupational status and gender seem to modify some of these developments. This study provides some support for inter-cohort changes in the work environment and health, predominantly among younger cohorts. More recent cohorts generally report poorer health and work environment along with less favourable development with age. Nevertheless, these patterns are not consistent across all age group comparisons and robust cohort comparisons are primarily possible among adjacent cohorts. It is, however, unlikely that these changes can be attributed solely to a general deterioration in working life affecting all workers equally, as the phenomenon appears largely confined to younger workers. Future studies should explore how the combined demands from several spheres of life may better explain these age and cohort differences.

BackgroundEarly childhood home environment is intricately linked to child development and later cognitive and academic skills. There is limited literature evaluating home environmental trends and predictors in the low‐ and middle‐income country settings.AimsDetermine the trends of early childhood home environment changes between 6 and 36 months of age, and the factors associated with these changes.Study designLongitudinal community‐based birth cohort follow‐up study in a semi‐urban slum in Vellore, South India.SubjectsConsecutive sampling of a birth cohort between March 2010 and February 2012.Outcome measuresHome environment was objectively assessed using the ‘Home Observation for the Measurement of the Environment’ (HOME) scale. Predictors of change in the home environment over time also were analyzed. Multivariable linear regression models and linear mixed effect models were used to identify the factors associated with HOME score at individual time points and over‐a‐time period, respectively.ResultsThe birth cohort enrolled 251 children with a follow‐up of 235, 228 and 218 children at 6, 24 and 36 months, respectively. The socio‐economic status (SES) was the single biggest predictor for the HOME score at each time point, with increasing strength over time. Maternal education predicted home environment at 24 months, while maternal depression was negatively associated at 6 and 24 months of age. SES and maternal factors contributed to the overall change in the HOME score. Maternal factors predicted relational home environmental change over time.ConclusionSES and maternal factors consistently predicted early childhood home environment at 6, 24 and 36 months of age and its change over time. It is important to support maternal education and wellbeing along with socio‐economic measures to optimize early childhood environment.

The prenatal environment is of fundamental importance for the fetus, as the fetus is particularly susceptible to environmental influences while in utero, and several prenatal adversities may constitute a risk factor for fetal growth and child development. Intrauterine growth restriction (IUGR) refers to a pregnancy complication involving the inadequate growth of the fetus in utero, with potential programming consequences on the children's brain-behavior development. In this narrative review we will discuss the most recent literature about IUGR children, including their development and their relationship with the prenatal and postnatal environment. In particular, as an attempt to an adaptive response to intrauterine changes, the brain development of IUGR fetuses follows abnormal developmental pathways, which likely has cascade effects on the future neurodevelopmental outcomes of the children. Cognitive and motor functions are in fact impaired, as well as IUGR children present, across studies, poor socio-emotional abilities and a greater risk for internalizing and externalizing behavior problems. The current work also highlights how the postnatal environment, and in particular parental care, has an important role in IUGR development, acting as a protective factor, or otherwise increasing their constitutional vulnerabilities. Overall, this narrative review has important implications for clinical practice, suggesting the need for long-term follow-up care with IUGR children and strategies supporting parent-child interactions as well.