Involuntary tobacco smoke exposures from conception to 18 years increase midlife cardiometabolic disease risk: a 40-year longitudinal study.

Few population studies have sufficient follow-up period to examine early-life exposures with later life diseases. A critical question is whether involuntary exposure to tobacco smoke from conception to adulthood increases the risk of cardiometabolic diseases (CMD) in midlife. In the Collaborative Perinatal Project, serum-validated maternal smoking during pregnancy (MSP) was assessed in the 1960s. At a mean age of 39 years, 1623 offspring were followed-up for the age at first physician-diagnoses of any CMDs, including diabetes, heart disease, hypertension, or hyperlipidemia. Detailed information on their exposure to environmental tobacco smoke (ETS) in childhood and adolescence was collected with a validated questionnaire. Cox regression was used to examine associations of in utero exposure to MSP and exposure to ETS from birth to 18 years with lifetime incidence of CMD, adjusting for potential confounders. We calculated midlife cumulative incidences of hyperlipidemia (25.2%), hypertension (14.9%), diabetes (3.9%), and heart disease (1.5%). Lifetime risk of hypertension increased by the 2^nd -trimester exposure to MSP (adjusted hazard ratio: 1.29, 95% confidence interval: 1.01-1.65), ETS in childhood (1.11, 0.99-1.23) and adolescence (1.22, 1.04-1.44). Lifetime risk of diabetes increased by joint exposures to MSP and ETS in childhood (1.23, 1.01-1.50) or adolescence (1.47, 1.02-2.10). These associations were stronger in males than females, in never-daily smokers than lifetime ever smokers. In conclusion, early-life involuntary exposure to tobacco smoke increases midlife risk of hypertension and diabetes in midlife.