Studies suggest decreased mortality risk among people who are overweight or obese compared with individuals with normal weight in type 2 diabetes (obesity paradox). However, the relationship between body weight or weight change and microvascular vs macrovascular complications of type 2 diabetes remains unresolved. Researchers investigated the association between BMI and BMI change with long-term risk of microvascular and macrovascular complications in type 2 diabetes in a prospective cohort study.
Researchers studied participants with incident type 2 diabetes from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam cohort, who were free of cancer, cardiovascular disease and microvascular disease at diagnosis (n?=?1083). Pre-diagnosis BMI and relative annual change between pre- and post-diagnosis BMI were evaluated in multivariable-adjusted Cox models.
-- There were 85 macrovascular (myocardial infarction and stroke) and 347 microvascular events (kidney disease, neuropathy and retinopathy) over a median follow-up of 10.8 years.
-- Median pre-diagnosis BMI was 29.9 kg/m2 and the median relative annual BMI change was ?0.4%.
-- Higher pre-diagnosis BMI was positively associated with total microvascular complications, kidney disease and neuropathy but not with macrovascular complications.
-- Analyses according to BMI categories corroborated these findings.
-- Effect modification was not evident by sex, smoking status or age groups.
-- In analyses according to BMI change categories, BMI loss of more than 1% indicated a decreased risk of total microvascular complications, kidney disease and neuropathy, compared with participants with a stable BMI; no clear association was observed for macrovascular complications.
-- The associations between BMI gain compared with stable BMI and diabetes-related vascular complications were less apparent.
-- Associations were consistent across strata of sex, age, pre-diagnosis BMI or medication but appeared to be stronger among never-smokers compared with current or former smokers.
Conclusively, among people with incident type 2 diabetes, pre-diagnosis BMI was positively associated with microvascular complications, while a reduced risk was observed with weight loss when compared with stable weight. The relationships with macrovascular disease were less clear.