As may be expected, lifestyle risk factors, including physical activity and diet, are found to be more influential in determining type 2 diabetes risk within a married couple than physiologic factors such as glucose tolerance or insulin sensitivity, researchers have shown.
"Essentially, these data suggest that couple-based interventions targeting spouses' similarities might be an efficient way of delivering lifestyle interventions," said study lead Omar Silverman-Retana, MD, PhD.
"We identified that spousal concordance was strongest for behavioral risk factors, in particular physical activity and diet," he told Medscape Medical News in an interview.
Silverman-Retana, of Steno Diabetes Center Aarhus, Aarhus University Hospital, Denmark, reported the findings in a poster at this year's Annual Meeting of the European Association for the Study of Diabetes (EASD), held online because of the coronavirus pandemic.
Effectively, concordance was found to be weaker in the pathophysiologic markers because these are more biologically determined compared with lifestyle factors.
Janice Kiecolt-Glaser, PhD, is a marital biobehavioral researcher who is interested in spousal concordance for many chronic health conditions.
This "research is part of a growing body of evidence that carries a clear message: be careful whom you marry, your life may depend on it!" she explained.
"Your partner's behavior definitely influences your own, and in the case of diabetes, the researchers have found clear behavioral links, and those make sense," she told Medscape Medical News.
"In addition, data from our lab and others show that the gut microbiomes of cohabiting couples are more similar than those of unrelated pairs," noted Kiecolt-Glaser, who is professor of psychiatry and behavioral Health at Ohio State University College of Medicine in Columbus.
"Diet and exercise both have substantial influences on the gut microbiome, and there is growing evidence that the gut microbiome contributes to risk for diabetes. This research fits with, and extends, what we know."
A Comprehensive Picture of Mechanisms Leading to Diabetes
The research led by Silverman-Retana and colleagues comprised a cross-sectional analysis of couples who participated in The Maastricht Study, an extensive phenotyping trial that focuses on the causes of type 2 diabetes, its classic complications, and its emerging comorbidities.
The researchers measured a comprehensive list of lifestyle and physiologic indicators, and using the social network aspect of the study, identified 172 couples with complete information for the final analysis.
Spousal concordance in lifestyle factors and pathophysiologic mechanisms of type 2 diabetes, including beta cell function and insulin sensitivity, were determined using regression analysis. Risk factors included waist circumference, percentage body fat, physical activity, sedentary time, the Dutch Healthy Diet Index (DHDI), and total energy consumption.
In addition, the researchers assessed glucose metabolism status using fasting and 2-hour plasma glucose, as well as HbA1c, and they also derived beta cell function indices using a seven-time point glucose tolerance test, and insulin sensitivity.
"Most importantly, we measured risk factors and pathophysiologic factors in the same study, and to the same level of detail in both partners, providing a more comprehensive picture of the mechanisms that lead to type 2 diabetes," Silverman-Retana highlighted.
There have been previous studies addressing disease risk and couples' concordance. A prior study, also by Silverman-Retana and colleagues at Aarhus University, found a link between the weight of one spouse and the chances of a diagnosis of type 2 diabetes in the other spouse.
Another study, reported by Medscape Medical News in 2018, showed that when one spouse tried to lose weight with a weight management program, the other 'untreated' spouse was also likely to drop some weight too.
Silverman-Retana noted that other research examining the similarities and differences within couples has investigated physical activity using self-reported questionnaires, but the current study used accelerometer data. "These provide a more precise measure of physical activity," he said, in pointing out one way in which the new study differs from previous ones.
The findings suggest that for men, the strongest spousal concordance was for the Dutch Healthy Diet Index (DHDI), meaning that a one unit increase in wives' DHDI was associated with a 0.53 unit difference in the men's DHDI.
For women, the strongest concordance was for the time spent in high intensity physical activity, such that a one unit increase in husbands' time spent in high intensity physical activity was associated with a 0.36 unit difference in women's time spent in high intensity physical activity.
"If we compare the concordance, it weakens as we move downstream to the immediate causal risk factors of type 2 diabetes," explained Silverman-Retana. "The weakest concordance was found in beta cell function indices and glucose metabolism indicators because these are more biologically determined."
Concordance is mainly explained by the fact that we tend to choose a partner who has similar characteristics to our own, in terms of social class and/or educational level, smoking status, exercise habits and diet, explained the researcher.
"It would be interesting to know how behavioral similarity depends on the length of marriage or time as a couple. Future studies will need to look into this," he concluded.
Silverman-Retana and Kiecolt-Glaser have disclosed no relevant financial relationships.
Annual Meeting of the European Association for the Study of Diabetes (EASD): Abstract 332. Presented September 21-25, 2020.
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