Prospective study of breakfast frequency and timing and the risk of incident type 2 diabetes in community-dwelling older adults: the Cardiovascular Health Study

Background No evidence-based recommendations regarding optimal breakfast frequency and timing and type 2 diabetes mellitus (T2DM) exist for older adults because of limited studies. Objectives We sought to prospectively assess relations between breakfast frequency and timing and T2DM risk among older adults and determine whether these depended on sex or cardiometabolic risk factors. Methods Weekly breakfast frequency and usual daily breakfast time were assessed by questionnaire at baseline in 3747 older adults (aged >= 65 y) from the Cardiovascular Health Study (CHS) who were free of cancer and T2DM and followed for 17.6 y. Multivariable-adjusted hazard ratios (aHRs) with 95% CIs estimated from Cox proportional hazards models were used to quantify associations with T2DM. Results Most CHS participants (median age: 74 y; IQR: 71-78 y) consumed breakfast daily (85.5%), and 73% had their first daily eating occasion between 07:00 and 09:00, both of which were associated with higher socioeconomic status, factors that are indicative of a healthier lifestyle, and lower levels of cardiometabolic risk indicators at baseline. During follow-up, 547 T2DM cases were documented. No strong evidence was observed linking breakfast frequency and risk of T2DM. Compared with participants whose breakfast timing (first eating occasion of the day) was 07:00-09:00, those who broke fast after 09:00 had an aHR for T2DM of 0.71 (95% CI: 0.51, 0.99). This association was present in participants with impaired fasting glucose at baseline (aHR: 0.61; 95% CI: 0.39, 0.95) but not in those without (aHR: 0.83; 95% CI: 0.50, 1.38). No associations between eating frequency or timing and T2DM were observed within other prespecified subgroups. Conclusions Eating breakfast daily was not associated with either higher or lower risk of T2DM in this cohort of older adults, whereas a later (after 09:00) daily first eating occasion time was associated with lower T2DM risk in participants with impaired fasting glucose at baseline. This trial was registered at clinicaltrials.gov as NCT00005133.