Childhood obesity increases risk of type 1 diabetes
Researchers analyzed human genetic data from 454,023 individuals from the UK Biobank and 15,573 type 1 diabetes cases from other cohorts and applied a scientific technique called Mendelian Randomization (MR) to provide evidence that childhood adiposity increases type 1 diabetes risk. As an individual's genetic alleles are fixed at birth, MR is typically more robust to confounding factors than conventional epidemiological studies. Furthermore, when adiposity differs between individuals, then whether that difference is due to environmental influences (such as diet or exercise) or is due to genetic influences will not change the increased disease risk caused by adiposity. This means that inferences regarding the consequences of obesity on disease risk from MR studies can be more reliable than from conventional observational studies.

The study's findings support the inference that greater adiposity in early life increases the risk of type 1 diabetes among individuals and that the increasing prevalence of childhood obesity likely contributes to the rising numbers of type 1 diabetes cases. Being overweight in childhood increases the risk of developing type 1 diabetes in later life. Being overweight over many years from childhood influences the risk of other diseases including asthma, eczema and hypothyroidism.