Background: The influence of overall lifestyle behaviors on diabetic microvascular complications remains unknown. In addition, the potential mediating biomarkers underlying the association is unclear. This study aimed to examine the associations of the combined lifestyle factors with risks of total and individual microvascular complications among patients with type 2 diabetes (T2D) and to explore the potential mediation effects of metabolic biomarkers. Methods and findings: This retrospective cohort study included 15,104 patients with T2D free of macro- and microvascular complications at baseline (2006 to 2010) from the UK Biobank. Healthy lifestyle behaviors included noncurrent smoking, recommended waist circumference, regular physical activity, healthy diet, and moderate alcohol drinking. Outcomes were ascertained using electronic health records. Over a median of 8.1 years of follow-up, 1,296 cases of the composite microvascular complications occurred, including 558 diabetic retinopathy, 625 diabetic kidney disease, and 315 diabetic neuropathy, with some patients having 2 or 3 microvascular complications simultaneously. After multivariable adjustment for sociodemographic characteristics, history of hypertension, glycemic control, and medication histories, the hazard ratios (95% confidence intervals (CIs)) for the participants adhering 4 to 5 low-risk lifestyle behaviors versus 0 to 1 were 0.65 (0.46, 0.91) for diabetic retinopathy, 0.43 (0.30, 0.61) for diabetic kidney disease, 0.46 (0.29, 0.74) for diabetic neuropathy, and 0.54 (0.43, 0.68) for the composite outcome (all Ps-trend ≤0.01). Further, the population-attributable fraction (95% CIs) of diabetic microvascular complications for poor adherence to the overall healthy lifestyle (<4 low-risk factors) ranged from 25.3% (10.0%, 39.4%) to 39.0% (17.7%, 56.8%). In addition, albumin, HDL-C, triglycerides, apolipoprotein A, C-reactive protein, and HbA_1c collectively explained 23.20% (12.70%, 38.50%) of the associations between overall lifestyle behaviors and total diabetic microvascular complications. The key limitation of the current analysis was the potential underreporting of microvascular complications because the cases were identified via electronic health records. Conclusions: Adherence to overall healthy lifestyle behaviors was associated with a significantly lower risk of microvascular complications in patients with T2D, and the favorable associations were partially mediated through improving biomarkers of glycemic control, systemic inflammation, liver function, and lipid profile.

OBJECTIVE: To test the causal effect of childhood BMI on adult cardiometabolic diseases using a Mendelian randomization analysis. RESEARCH DESIGN AND METHODS: We used 15 single nucleotide polymorphisms as instrumental variables for childhood BMI to test the causal effect of childhood BMI on cardiometabolic diseases using summary-level data from consortia. RESULTS: We found that a 1-SD increase in childhood BMI (kg/m2) was associated with an 83% increase in risk of type 2 diabetes (odds ratio [OR] 1.83 [95% CI 1.46, 2.30]; P = 2.5 × 10−7) and a 28% increase in risk of coronary artery disease (CAD) (OR 1.28 [95% CI 1.17, 1.39]; P = 2.1 × 10−8) at the Bonferroni-adjusted level of significance (P < 0.017) in adults. In addition, a 1-SD increase in childhood BMI was associated with a 0.587-SD increase in adulthood BMI (kg/m2), a 0.062-SD increase in hip circumference (cm), a 0.602-SD increase in waist circumference (cm), a 0.111 pmol/L increase in log fasting insulin, a 0.068 increase in log-transformed HOMA of ß-cell function (%), a 0.126 increase in log-transformed HOMA of insulin resistance (%), and a 0.109-SD increase in triglyceride (mg/dL) but a 0.138-SD decrease in HDL (mg/dL) in adults at the Bonferroni-adjusted level of significance (P < 0.0026). CONCLUSIONS: A genetic predisposition to higher childhood BMI was associated with increased risk of type 2 diabetes and CAD in adult life. These results provide evidence supportive of a causal association between childhood BMI and these outcomes.

OBJECTIVE: Evidence is limited regarding the associations between vitamin D status and microvascular complications in individuals with type 2 diabetes (T2D), among whom vitamin D deficiency or insufficiency is particularly common. In this study we aimed to prospectively investigate the associations of serum 25-hydroxyvitamin D [25(OH)D] and vitamin D receptor (VDR) polymorphisms with risk of diabetic microvascular complications. RESEARCH DESIGN AND METHODS: This analysis included 14,709 participants with T2D who were free of microvascular complications from the UK Biobank. Incidence of diabetic microvascular complications was ascertained via electronic health records. Cox proportional hazards regression models were used to estimate hazard ratios (HRs) and 95% CIs. RESULTS: Median serum 25(OH)D concentration was 40.7 nmol/L (interquartile range 27.5, 56.4). During a median of 11.2 years of follow-up, 1,370 people developed diabetic microvascular complications. Compared with participants with 25(OH)D <25 nmol/L, individuals with 25(OH)D ≥75 nmol/L had a multivariable-adjusted HR of 0.65 (95% CI 0.51, 0.84) for composite diabetic microvascular complications, 0.62 (0.40, 0.95) for diabetic retinopathy, 0.56 (0.40, 0.79) for diabetic nephropathy, and 0.48 (0.26, 0.89) for diabetic neuropathy. In addition, in comparisons with participants with 25(OH)D <25 nmol/L and minor allele homozygotes (TT of rs1544410 and GG of rs731236), the multivariable-adjusted HRs of composite diabetic microvascular complications were 0.54 (0.38, 0.78) and 0.55 (0.38, 0.80) for participants with serum 25(OH)D ≥50 nmol/L and major allele homozygotes (CC and AA), respectively, although no significant interaction was observed. CONCLUSIONS: Higher serum 25(OH)D concentrations were significantly associated with lower risk of diabetic microvascular complications, including diabetic retinopathy, diabetic nephropathy, and diabetic neuropathy. Our findings suggest a potential beneficial role of maintaining adequate vitamin D status in the prevention of diabetic microvascular complications.

Background: Several epidemiological studies have suggested that vitamin D status is associated with risk of dementia in general populations. However, due to the synergistic effect between diabetic pathology and neuroinflammation, and the prothrombotic profile in patients with diabetes, whether vitamin D is associated with risk of dementia among patients with diabetes is unclear. This study aimed to investigate the associations of circulating vitamin D levels with risks of all-cause dementia, Alzheimer disease (AD), and vascular dementia (VD) among adults with type 2 diabetes (T2D).Methods and findings: This study included 13,486 individuals (≥60 years) with T2D and free of dementia at recruitment (2006–2010) from the UK Biobank study. Serum 25-hydroxyvitamin D (25[OH]D) concentrations were measured using the chemiluminescent immunoassay method at recruitment. Serum 25(OH)D ≥ 75 nmol/L was considered sufficient, according to the Endocrine Society Clinical Practice Guidelines. Incidence of all-cause dementia, AD, and VD cases was ascertained using electronic health records (EHRs). Each participant’s person-years at risk were calculated from the date of recruitment to the date that dementia was reported, date of death, date of loss to follow-up, or 28 February 2018, whichever occurred first. Among the 13,486 individuals with T2D (mean age, 64.6 years; men, 64.3%), 38.3% had vitamin D ≥ 50 nmol/L and only 9.1% had vitamin D ≥ 75 nmol/L. During a mean follow-up of 8.5 years, we observed 283 cases of all-cause dementia, including 101 AD and 97 VD cases. Restricted cubic spline analysis demonstrated a nonlinear relationship between serum 25(OH)D and risk of all-cause dementia (P_nonlinearity< 0.001) and VD (P_nonlinearity= 0.007), and the nonlinear association reached borderline significance for AD (P_nonlinearity= 0.06), with a threshold at around a serum 25(OH)D value of 50 nmol/L for all the outcomes. Higher serum levels of 25(OH)D were significantly associated with a lower risk of all-cause dementia, AD, and VD. The multivariate hazard ratios and 95% confidence intervals for participants who had serum 25(OH)D ≥ 50 nmol/L, compared with those who were severely deficient (25[OH]D < 25 nmol/L), were 0.41 (0.29–0.60) for all-cause dementia (P_trend< 0.001), 0.50 (0.27–0.92) for AD (P_trend= 0.06), and 0.41 (0.22–0.77) for VD (P_trend= 0.01). The main limitation of the current analysis was the potential underreporting of dementia cases, as the cases were identified via EHRs.Conclusions: In this study, we observed that higher concentrations of serum 25(OH)D were significantly associated with a lower risk of all-cause dementia, AD, and VD among individuals with T2D. Our findings, if confirmed by replication, may have relevance for dementia prevention strategies that target improving or maintaining serum vitamin D concentrations among patients with T2D.