Millennials and gen Z are more likely to live with obesity and report mental health difficulties earlier in their lives than the baby boomers and generation X, finds a new review of studies comparing UK birth cohorts co-led by UCL academics.
The trend, described by researchers as a 'generational health drift', suggests that more recently born generations may spend more years living in ill health than their earlier born counterparts.
The review by researchers from UCL, King's College London and University of Oxford examined changes in the physical and mental health of multiple generations of people, including baby boomers born in 1946 and 1958, members of generation X born in 1970, millennials born in 1989-90 and gen Z born in 2000-02.
The findings, published in Population Studies, reveal:
- Rates of childhood overweight and obesity were highest among gen Z.
- Diabetes in midlife (age 44-48) almost doubled from 3.1% among the baby boomers to 5.9% in generation X.
- Gen Z exhibited higher levels of mental ill-health in adolescence compared to earlier born groups.
- Levels of life satisfaction were lower among millennials than generation X.
The researchers said the findings have implications for investment needed to care for increasing numbers living with long-term health conditions. Health has worsened despite declines in smoking, increasing educational attainment, and improvements in material circumstances early in life.
Lead author, PhD student Laura Gimeno (UCL Centre for Longitudinal Studies) said: "We're seeing the consequences of preventable social and environmental exposures that have shaped population health over time and across generations."
"The generational health drift has serious implications for policy, planning, and the funding allocations needed to be able to support a greater number of people living with long-term health conditions."
By 2050, a quarter of the British population will be aged 65 or over which will increase demands on health and social care systems and the economy. As such, it is important that people born more recently live not only longer but also in good health to meet the challenges of population aging.
Life expectancy in the UK improved dramatically during the twentieth century. More recent generations have experienced lower infant and child mortality and fewer deaths from heart disease.
However, increases in health expectancies have slowed or stalled since the early 2010s, driven by worsening health in midlife. Recently published data from the Office for National Statistics suggests that healthy life expectancy has fallen in recent years.
"These findings suggest that recent declines in healthy life expectancy are likely driven by a combination of worsening mental and physical health in more recent generations," says co-author, Professor George Ploubidis (UCL Centre for Longitudinal Studies).
This review drew on evidence from 51 studies published up to June 2024. All 51 papers focused on data from British birth cohort studies which have followed people born between 1946 and 2002. They are the National Survey of Health and Development, the 1958 National Child Development Study, the 1970 British Cohort Study, Next Steps, Avon Longitudinal Study of Parents and Children, and the Millennium Cohort Study.
The researchers found little suggestion of improvements in health for people born since 1946. They say more research is needed to understand the drivers of this trend which they add has probably been shaped by changing exposure to social and environmental risk factors (e.g., to "obesogenic environments") throughout peoples' lives, which are likely preventable.
The findings raise important questions about the apparent worsening of health, which the authors suggest is most plausibly driven by a genuine increase in poor health. Increasing survival rates are unlikely to explain the trend, given that generational differences are evident from early life through midlife. Similarly, the consistency of findings across both self-reported and objectively measured health outcomes makes it unlikely that changes in measurement alone underlie the observed pattern.
