Early-life exposure to sugar rationing and long-term risk of depression and anxiety: a population-based natural experiment.

Early-life nutritional environments, particularly during the first 1000 days of life, may have long-term implications for mental health. We investigated the association between early-life exposure to UK sugar rationing, a population-wide policy implemented during and after World War II, and the risk and timing of depression and anxiety in adulthood. The primary analysis included 64,381 UK Biobank participants born between October 1951 and March 1956 and recruited between 2006 and 2010. Exposure to sugar rationing during gestation and the first two years after birth was classified according to birth timing relative to the termination of UK sugar rationing in September 1953. Associations with depression, anxiety, and their composite outcome were examined using Gompertz parametric survival models, with additional age-at-onset analyses to assess whether early-life exposure influenced the timing of disease onset. Cross-cohort analyses were conducted in the English Longitudinal Study of Ageing as a UK-based replication cohort and in the U.S. Health and Retirement Study as a negative comparator cohort not exposed to the UK sugar rationing policy. Participants exposed to sugar rationing in early life had lower hazards of both depression and anxiety, with the greatest risk reduction observed among those exposed in utero plus up to two years after birth. Compared with unexposed individuals, this group had a 17% lower hazard of depression (HR = 0.83, 95% CI: 0.79-0.87) and a 23% lower hazard of anxiety (HR = 0.77, 95% CI: 0.72-0.82). Exposure limited to the prenatal period alone was not consistently associated with depression or anxiety. Longer durations of early-life exposure were also associated with later disease onset, with delays of up to 2.37 years for depression and 4.69 years for anxiety. Similar inverse associations were observed in the English Longitudinal Study of Ageing, but not in the Health and Retirement Study. These findings suggest that exposure to sugar restriction during the first 1000 days of life, particularly when extending into infancy and early childhood, is associated with lower risks and delayed onset of depression and anxiety in later life.