Bahareh Rasouli, Tomas Andersson, Valdemar Grill, Kristian Midthjell, Lisa Olsson and Sofia Carlsson
Introduction: Adult-onset autoimmune diabetes is prevalent, yet there are limited data on risk factors.
Aim: Our aim was to examine how combinations of modifiable lifestyle factors are associated with risk of adultonset autoimmune diabetes and to estimate the Population Attributable Risk (PAR) related to such factors.
Methods: We used incidence data from Nord-Trøndelag Health Survey Study (HUNT), a large population-based study where adults aged ≥ 20 years old were investigated in three consecutive surveys during 1984-2008 (n=49,712; eligible for this study).Among self-reported diabetes patients, presence of Glutamic Acid Decarboxylase Antibodies (GADA) and age at onset ≥ 35 years old were used to identify incident cases of adult-onset autoimmune diabetes (n=164). Hazard Ratios (HR) of autoimmune diabetes by lifestyle factors were estimated by Cox regression and PAR were calculated for single items and combination of lifestyle factors.
Results: A reduced risk of adult-onset autoimmune diabetes was conferred by BMI<25, physical activity, regular alcohol consumption and psychosocial well-being. Positivity for all four healthy lifestyle factors gave a HR of 0.10 (95% CI=0.02-0.40) compared with no positivity. Estimation of PAR indicated that 69% (CI=45-79%) of all cases of adult-onset autoimmune diabetes could be prevented through these factors with BMI< 25 as the most important contributor (PAR for BMI ≥ 25= 34%, CI=20-48%).
Conclusions: Provided that these associations are causal, then the majority of adult-onset autoimmune diabetes cases are preventable by modification of common lifestyle factors primarily by maintaining a BMI in the non-overweight range.