OBJECTIVELow weight has been associated with increased mortality risks in type 1 diabetes. We aimed to investigate the importance of weight and weight gain/loss in the Swedish population diagnosed with type 1 diabetes. RESEARCH DESIGN AND METHODSPatients with type 1 diabetes (n = 26,125; mean age 33.3 years; 45% women) registered in the Swedish National Diabetes Registry from 1998 to 2012 were followed from the first day of study entry. Cox regression was used to calculate risk of death from cardiovascular disease (CVD), major CVD events, hospitalizations for heart failure (HF), and total deaths. RESULTSPopulation mean BMI in patients with type 1 diabetes increased from 24.7 to 25.7 kg/m 2 from 1998 to 2012. Over a median follow-up of 10.9 years, there were 1,031 deaths (33.2% from CVD), 1,460 major CVD events, and 580 hospitalizations for HF. After exclusion of smokers, patients with poor metabolic control, and patients with a short follow-up time, there was no increased risk for mortality in those with BMI <25 kg/m 2 , while BMI >25 kg/m 2 was associated with a minor increase in risk of mortality, major CVD, and HF. In women, associations with BMI were largely absent. Weight gain implied an increased risk of mortality and HF, while weight loss was not associated with higher risk. CONCLUSIONSRisk of major CVD, HF, CVD death, and mortality increased with increasing BMI, with associations more apparent in men than in women. After exclusion of factors associated with reverse causality, there was no evidence of an obesity paradox.Recent studies suggest that insulin resistance in overweight or obese individuals with type 1 diabetes may be associated with an increased risk of vascular complications (1), but few studies have investigated the relationship between BMI in individuals with type 1 diabetes and mortality. Phenomena such as the obesity paradox, which suggests that there is an inverse association between BMI and risk of cardiovascular outcomes, have been debated intensely in the past decade (2). Also, the prevalence of obesity in the general Swedish population has increased steadily over past decades (3), and for patients with type 1 diabetes, weight gain is a potential side effect of intensive insulin therapy, which is the mainstay of modern management (4). Hence, to our

Aims/hypothesisType 2 diabetes is an established risk factor for heart failure, but age-specific data are sparse. We aimed to determine excess risk of heart failure, based on age, glycaemic control and kidney function in comparison with age- and sex-matched control individuals from the general population.MethodsIndividuals with type 2 diabetes registered in the Swedish National Diabetes Registry 1998–2012 (n = 266,305) were compared with age-, sex- and county-matched control individuals without diabetes (n = 1,323,504), and followed over a median of 5.6 years until 31 December 2013.ResultsWe identified 266,305 individuals with type 2 diabetes (mean age 62.0 years, 45.3% women) and 1,323,504 control individuals. Of the individuals with type 2 diabetes and control individuals, 18,715 (7.0%) and 50,157 (3.8%) were hospitalised with a diagnosis of heart failure, respectively. Comparing individuals with diabetes with those in the control group, men and women with type 2 diabetes who were younger than 55 years of age had HRs for hospitalisation for heart failure of 2.07 (95% CI 1.73, 2.48) and 4.59 (95% CI 3.50, 6.02), respectively, using analyses adjusted for socioeconomic variables and associated conditions. Younger age, poorer glycaemic control and deteriorating renal function were all associated with increased excess risk of heart failure in those with type 2 diabetes compared with the control group. However, people with diabetes who were ≥75 years and without albuminuria or with good glycaemic control (HbA1c ≤52 mmol/mol [≤6.9%]) had a similar risk of hospitalisation for heart failure as control individuals in the same age group.Conclusions/interpretationMen and women aged <55 years with type 2 diabetes are at markedly elevated excess risk of heart failure. The excess risk declined with age, but persisted even with good glycaemic control. However, among those who were 75 years and older, diabetic individuals with well controlled glucose levels or without albuminuria had a risk of heart failure that was on a par with individuals without diabetes.Electronic supplementary materialThe online version of this article (10.1007/s00125-018-4700-5) contains peer-reviewed but unedited supplementary material, which is available to authorised users.

Our findings suggest that the apparent paradoxical findings in other studies in this area may have been affected by reverse causality. Long-term, overweight (BMI 25 to <30 kg/m) patients with type 2 diabetes had low excess mortality risk compared with control subjects, whereas risk in those with BMI ≥40 kg/m was substantially increased.