TV viewing during childhood and adult type 2 diabetes mellitus.

We examined whether regular television (TV) viewing at ages 3-5 and 5-10 years is related to the incidence of type 2 diabetes mellitus (T2D) in adult women. We used data from 34,512 mother-nurse daughter dyads in the Nurses' Health Study (NHS) II and the Nurses' Mothers' Cohort Study. Mothers of NHS II participants completed a questionnaire on their pregnancy with the nurse and her early life experience. During 391,442 person-years of follow-up from 2001 to 2013, 1515 nurses developed T2D. Increasing levels of TV viewing at 3-5 years of age retrospectively reported by the mothers were related to a greater risk of T2D in adulthood: multivariable-adjusted hazard ratios (HRs) for ≤ 1, 2, and ≥ 3 h/day vs. no TV viewing were 1.11 [95% confidence interval (CI) 0.96-1.28], 1.20 (95% CI 1.02-1.41), and 1.35 (95% CI 1.11-1.65), p trend = 0.002, respectively, after adjustment for early life variables, including childhood physical activity and adiposity. Retrospectively reported TV viewing for ≥ 3 h/day at 5-10 years of age was associated with a 34% greater risk of adult T2D (HR 1.34, 95% CI 1.05-1.70, p trend < 0.001). Additional adjustments for adult variables, including adult TV viewing and current BMI attenuated the effect estimates (≥ 3 h/day TV viewing at 3-5 years: HR 1.22, 95% CI 0.99-1.49, p trend = 0.07; TV viewing at 5-10 years: 1.16, 95% CI 0.91-1.49, p trend = 0.09). The present study suggests that TV viewing during early childhood increases risk of T2D in adult women; adult BMI explains part of this association. Further research is required to confirm this observation and understand the mediating pathways.