Dorothy D. Sears
Longer sitting bout duration conferred worse parameters of CVD risk in women, but the effect on blood sugar/glucose was most pronounced in Hispanic women, according to a study published in a Go Red for Women-focused issue of the Journal of the American Heart Association.
“Prolonged sitting time is a cardiometabolic health risk in this population and should be discussed by clinical and health care professionals with patients,” Dorothy D. Sears, PhD, professor of nutrition at the Arizona State University College of Health Solutions in Phoenix, told Healio. “Clinicians and other health care providers should encourage patients to reduce their sitting time, total daily sitting time and uninterrupted bouts of sitting, in addition to encouraging physical activity.”
Data from postmenopausal women
For the cross-sectional study, researchers analyzed data from 518 women (mean age, 63 years) with overweight or obesity who were postmenopausal from three different studies. In all three studies, women wore accelerometers for up to 14 days to assess sitting patterns and total sitting time.
Cardiometabolic risk markers evaluated included waist circumference, BMI, fasting insulin, fasting glucose and homeostatic model assessment of insulin resistance (HOMA-IR). Several secondary outcome measures of interest included LDL, total cholesterol, HDL and triglycerides.
Among the cohort, 102 women were Hispanic and 416 were non-Hispanic. Differences were observed in total sitting and sitting patterns between Hispanic and non-Hispanic women after adjusting for physical functioning, education, age and Hispanic ethnicity. Compared with non-Hispanic women, Hispanic women had shorter sitting bout durations by 3.6 minutes (P = .02) and spent 50.3 fewer minutes sitting per day (P < .001).
Each additional hour of sitting was linked to the following:
- 1.71% higher waist circumference (95% CI, 0.62-2.81);
- 1.56% higher BMI (95% CI, 0.8-2.33);
- 7.27% higher HOMA-IR index (95% CI, 3.35-11.35); and
- 6.38% higher fasting insulin (95% CI, 2.86-10.02; P for trend for all associations < .01).
After multivariable adjustment, sitting bout duration was associated with waist circumference (1.93%; 95% CI, 0.31-3.57; P for trend = .02), BMI (1.64%; 95% CI, 0.5-2.79; P for trend = .005), fasting insulin (7.43%; 95% CI, 2.19-12.95; P for trend = .005), fasting glucose (1.36%; 95% CI, 0.06-2.68; P for trend = .041) and HOMA-IR index (8.92%; 95% CI, 3.05-15.13; P for trend < .01). All associations except for fasting glucose were statistically significant after adjusting for moderate to vigorous physical activity.
Sitting and fasting glucose
The link between sitting bout duration and fasting glucose was stronger in Hispanic women compared with non-Hispanic women (P for interaction = .03). Each 15-minute longer duration of sitting for Hispanic women was associated with a 4.8% higher fasting glucose level (95% CI, 0.5-9.37) compared with 0.9% for non-Hispanic women (95% CI, –0.4 to 2.22). Although not statistically significant, similar patterns were observed for higher HOMA-IR index (P = .22), insulin (P = .42) and waist circumference (P = .46).
“Our study was a single timepoint cross-sectional study looking at associations,” Sears said in an interview. “Studies with multiple timepoint measures over time are needed. We are engaged in three large controlled research studies that aim to reduce sitting time in sedentary postmenopausal women. We are very interested to see if cardiometabolic (heart and diabetes) risk is reduced in these women when their sitting time is reduced. These intervention studies will also inform us about what recommendations we can make to the public about how and how often to break up sitting time and support healthy aging.” – by Darlene Dobkowski
For more information:
Dorothy D. Sears, PhD, can be reached at firstname.lastname@example.org.
Disclosures: The authors report no relevant financial disclosures.