Prospective association between late evening food consumption and risk of prediabetes and diabetes: the Whitehall II cohort study.

AIMS: We examined whether late evening food consumption was prospectively associated with the risk of developing prediabetes or diabetes in a large observational study of individuals with normoglycaemia. METHODS: Participants were 2642 men and women with normoglycaemia (HbA1c < 39 mmol/mol; < 5.7%) from the Whitehall II study. Time of last eating episode (TLEE) before the examination day was assessed at baseline. We studied the associations of TLEE with 5-year changes in HbA1c and risk of developing prediabetes or diabetes (HbA1c ≥ 39 mmol/mol; ≥ 5.7%). Potential heterogeneity in the association between TLEE and prediabetes or diabetes was examined using recursive partitioning modelling for time-to-event outcomes. RESULTS: There was a tendency of an overall association of TLEE with change in HbA1c but with little effect size [ß per 1-h increase in TLEE = 0.2 mmol/mol, 95% CI -0.0 to 0.3 (0.01%, -0.00 to 0.03); P = 0.055] and no association with the risk of developing prediabetes/diabetes (risk ratio per 1-h increase in TLEE = 1.03, 95% CI 0.94 to 1.13; P = 0.511). According to the recursive partitioning modelling, women with HbA1c ≤ 36 mmol/mol and TLEE after 21:00 had a 1.51 times (95% CI 1.16 to 1.93) higher 5-year risk of developing prediabetes or diabetes than those having their TLEE between 16:00 and 21:00 (35.4% vs. 23.5%; P = 0.003). CONCLUSIONS: There was no overall association of TLEE with the development of prediabetes or diabetes in the Whitehall II population. However, explorative analyses suggested that eating late in the evening was associated with increased risk of developing prediabetes/diabetes among women with good glycaemic control. Whether restricting late evening food consumption is effective and feasible for the prevention of Type 2 diabetes needs testing in randomized controlled trials.

Trajectories of obesity by spousal diabetes status in the English Longitudinal Study of Ageing.

AIMS: To examine whether the development of obesity with age was different for individuals with and without a spouse with diabetes. METHODS: We analysed data from the English Longitudinal Study of Ageing [n= 7123, median (interquartile range) age 59 (53-67) years, 51% men], which included four clinical examination waves between 1998 and 2012. The main exposure was having a spouse with diabetes. Outcomes of interest were BMI and waist circumference. We fitted quadratic age-related trajectories using mixed-effect models stratified by sex and adjusted for education, smoking and the corresponding interaction terms between age and spousal diabetes status. RESULTS: The baseline spousal diabetes prevalence was 4.4%. Men with a wife with diabetes experienced a steeper increase in BMI (1.6 kg/m2 ) between ages 50 to 65 years than men with a wife without diabetes (0.9 kg/m2 ). Women with a husband with diabetes had a similarly shaped BMI trajectory to women with a husband without diabetes, but their average BMI levels were higher between ages 55 and 65 years. Waist circumference trajectories showed a similar shape by spousal diabetes status for men and women, although individuals with a spouse with diabetes had higher waist circumference values throughout follow-up. CONCLUSIONS: We found a positive association between spousal diabetes status and obesity development, which differed by sex among middle-aged individuals. Evidence from couple-based interventions is needed to test whether the latter could improve the current individual-focused public health strategies for obesity prevention.

Effect of time of day and fasting duration on measures of glycaemia: analysis from the Whitehall II Study.

AIMS/HYPOTHESIS: We aimed to study diurnal variation in glucose regulation by examining the effects of time of day and fasting duration on fasting plasma glucose (FPG), 2 h post-load plasma glucose (2hPG) and HbA(1c) levels. METHODS: We analysed data from 5,978 non-diabetic white men and women from the prospective Whitehall II Study. All studied participants fasted for at least 8 h before a clinical examination, which included an OGTT and anthropometric measurements. We fitted mixed-effects models for FPG, 2hPG and HbA(1c) as outcome variables, and time of day and/or fasting duration as explanatory variables. Models were adjusted for age, BMI and study phase. RESULTS: Time of day and fasting duration were associated inversely with FPG and positively with 2hPG. The mean difference between measures at 08:00 and 15:00 hours in men/women was -0.46 (95% CI -0.50, -0.42) mmol/l/-0.39 (95% CI -0.46, -0.31) mmol/l and 1.39 (95% CI 1.25, 1.52) mmol/l/1.19 (95% CI 0.96, 1.42) mmol/l for FPG and 2hPG, respectively. HbA(1c) levels were independent of either time. Time of day and fasting duration were independently associated with 2hPG. In contrast, the effect of fasting duration on FPG was markedly attenuated with adjustment for time of day. Ageing, but not obesity, was associated with increased diurnal variation in glucose tolerance. CONCLUSIONS/INTERPRETATION: Both time of day and fasting duration should be considered in clinical practice and epidemiological studies, since they have clinically relevant effects on FPG and 2hPG levels. As biochemically expected, HbA(1c) levels are independent of time of blood sampling and fasting duration.