Does body size in early life matter more or less than adult adiposity in the development of diseases like diabetes?
High body mass index (BMI) in early life is thought to increase the risk of developing chronic conditions like diabetes as an adult. It is challenging to study, as many people who have larger body sizes as children continue with the same patterns into adulthood; it is unclear whether adulthood lifestyle changes can mitigate these risks. Additionally, there are genetic components involved in body composition as well as in the risk of developing morbidities such as diabetes.
A study published in March 2020 by the British Journal of Medicine investigates the extent to which the correlation between genetically predicted early life body size and the development of diabetes exists, and whether it is reversible by lifestyle changes in adulthood. The study analyzed participants from the UK Biobank study, which took place between 2006 and 2010. It collected health data from 500,000 adults of European descent who were between 40-69 years of age, at 22 assessment centers in the United Kingdom. Data collected was based on clinical examinations, genome-wide genotyping, biological sample assays, and self-reported health characteristics. Participant BMI was taken, and they were then asked to perceive their early life body size by responding to the question, “When you were ten years old, compared to average, would you describe yourself as thinner, plumper, or about average?” Patients were excluded if they did not provide informed consent, if there was a mismatch between reported sex, or in the case of sex chromosome aneuploidy. A total of 453,169 participants were chosen from the UK Biobank study who then underwent a genome-wide association study (GWAS) to identify genetic components associated with weight and other comorbidities. This was done so that both univariable and multivariable analyses could be performed to determine whether early-life body size has an independent association with disease risk, or whether the effect changes with adult body size.
Results of the study showed that those with an early life body size genetically predicted to be more significant are associated with increased odds of developing type 2 diabetes, shown statistically with an odds ratio of 2.32 and a confidence interval of 95% (1.33-1.68.) However, it was not shown that this result was independent of adult body size. This suggests that those with increased odds of larger body size in early life typically develop diabetes because they retain that larger body size through later life. It can be reasoned from the study results that overweight children who can lower their BMI later in adulthood can minimize the risk of diabetes.
The study conclusion that adulthood BMI is a more reliable predictor for diabetes development than childhood body size is encouraging. Patients with increased BMI in early childhood are not doomed to have diabetes if appropriate lifestyle modifications can be made to manage weight. This study’s greatest strength was its large sample size of 453,169 participants; however, it did have its limitations. The early-life body size measures were based on a retrospective questionnaire performed by the patients themselves, which means that patients’ subjective factors can skew it. The study would have been more robust if childhood medical record data were available to the researchers. Another limitation of the study was that all participants were of European origin. Future studies can be done in more diverse populations to make this study more applicable to more populations
- The incidence of type 2 diabetes is more related to being overweight in adulthood compared to childhood adiposity.
- Patients who were overweight in early life can minimize the risk of developing diabetes by controlling their BMIs later in life.
- Being overweight later in life causes an increased risk of developing chronic diseases such as diabetes versus a higher body mass in early life.
Reference for “Effects Of Early And Late-life Adiposity On The Risk Of Diabetes”:
Richardson, Tom G, et al. “Use of Genetic Variation to Separate the Effects of Early and Later Life Adiposity on Disease Risk: Mendelian Randomisation Study.” BMJ June 2020, p. m1203., doi:10.1136/bmj.m1203.
Sameen Khan, Pharm.D. Candidate, USF College of Pharmacy