Symposium: The Generational Health Drift: Understanding Causes and Consequences Using the British Birth Cohort Studies
The Generational Health Drift: Evidence from the British birth cohorts (George Ploubidis, UCL Centre for Longitudinal Studies)
Improving health and care has been at the forefront of election campaigns and manifestos in the United Kingdom for decades. Given continued improvements in life expectancy, increasing the number of years spent in good health is essential to supporting an ageing population. This presentation will highlight the unique contribution that the British birth cohort studies can provide on how physical and mental health has changed across generations, presenting findings from a systematic review of studies that have compared the health of cohort members born in 1946, 1958, 1970, the early 1990s, and the early 2000s at the same age. More recently born British cohorts are suffering from worse mental health, and a higher prevalence of diabetes, asthma, and obesity compared to previous generations. Evidence for improvements in health is scarce. We name this pattern of earlier onset of health decline the “Generational Health drift”. This trend reflects the impact of changing environmental and social exposures across the life course and has considerable implications for population ageing and the economy.
What explains increasing diabetes prevalence across cohorts? A causal mediation analysis in the 1958 and 1970 British birth cohorts (Laura Gimeno, UCL Centre for Longitudinal Studies)
Diabetes prevalence has increased across successive generations. The richness of the data collected by the British birth cohort studies offers a unique opportunity to explore what factors explain such cohort differences in health, with potential to inform efforts to reverse the Generational Health Drift. Using data from the 1958 and 1970 British birth cohorts, we (i) quantify cohort differences in HbA1c-measured diabetes at age 44-48, and (ii) use a causal mediation approach to test the contribution of six hypothesised mediators (obesity, psychological distress, housing tenure, relative poverty, breastfeeding, and maternal smoking during pregnancy), using the parametric g formula. Diabetes prevalence was higher in the 1970 cohort (6.5% vs. 3%). Obesity was the most important mediator of the cohort-diabetes association, mediating nearly 30% of the cohort-diabetes association, with psychological distress and housing tenure also contributing to the gap (6.4% and 6.9% mediated respectively). Given increases in obesity prevalence and mental ill-health across cohorts born since 1970, our results highlight the importance of tackling both obesity and wider social determinants of health to halt or reverse the Generational Health Drift in diabetes.
Weight loss and economic activity in the 1970 British Cohort Study (Charis Bridger Staatz , UCL Centre for Longitudinal Studies)
In the United Kingdom, the number of people who are not working due to their health has increased. Despite expansion of weight-loss medication, little evidence exists on whether weight loss is associated with a lower risk of economic inactivity. Leveraging life course data from the 1970 British birth cohort, we identify individuals who gained, lost, maintained their weight or weight cycled between ages 46 and 51-54, relative to their highest recorded adult body mass index (BMI) before age 42. We quantify associations between weight-change categories and subsequent economic inactivity. Only 4% of cohort members lost >5% of body weight from a previously obese BMI, 19% maintained a healthy BMI, 39% maintained overweight, and 38% maintained, gained, or cycled within obesity. Individuals who lost weight were more socioeconomically and physically disadvantaged, and weight loss in later midlife did not appear to offset the long-term effects of this disadvantage. After adjusting for previous economic activity and a wide range of sociodemographic controls, only continued obesity weight gain, affecting 1-in-5 adults, was associated with health-related economic inactivity (RRR = 1.69, 95% CI 1.08–2.63), underscoring the importance of preventing continued weight gain.
