Social Clustering Increases Diabetes Risk

Researchers at McGill University (Montreal, QC, Canada) selected cross-sectional, case control, and cohort studies examining spousal association for diabetes and/or prediabetes (impaired fasting glucose or impaired glucose tolerance), as indexed in Medline, Embase, or Scopus, between January 1, 1997 and February 28, 2013. Effect estimates with body mass index (BMI) adjustment were pooled separately from those without BMI adjustment to distinguish BMI-dependent and independent concordance. The researchers identified 2,705 articles, of which 6 were retained (involving 75,498 couples) for systematic review, and 5 for meta-analysis.

The results suggest that a spousal history of diabetes is associated with a 26% diabetes risk increase for the healthy partner. Furthermore, from studies that performed their own blood tests and detected undiagnosed diabetes, the researchers found that the risk of developing type 2 diabetes doubles for those with partners who have the condition. According to the researchers, the increased risk could be a result of social clustering, i.e., living in the same environments, adopting the same social habits, following similar eating patterns, and carrying out similar levels of exercise, all factors that can determine the risk of developing type 2 diabetes.

Additionally, the research team hypothesized that another factor, which they termed assortative mating, may also play a part; i.e., people seek out partners who possess similar characteristics to themselves. The researchers suggest that recognizing that a shared risk between spouses exists may improve diabetes detection and motivate couples to increase collaborative efforts to optimize eating and physical activity habits. The study was published in the January 24, 2014, issue of BMC Medicine.

“When we talk about family history of type 2 diabetes, we generally assume that the risk increase that clusters in families results from genetic factors. What our analyses demonstrate is that risk is shared by spouses,” said senior author associate professor Kaberi Dasgupta, MD, MSc. “This underscores the effects of shared environments, attitudes, and behaviors, which presumably underlie the shared risk. Our results are not the finding of a single study but rather a synthesis of the existing studies.”

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