Low Fitness Levels Increase All-Cause Mortality in Women With Metabolic Syndrome

Higher fitness levels decrease the risk for all-cause mortality in women with metabolic syndrome, according to study results published in Metabolic Syndrome and Related Disorders.

Researchers conducted a prospective study to determine the relationship between cardiorespiratory fitness and all-cause mortality in women with metabolic syndrome. A total of 1798 women (mean age, 50.2 years) with metabolic syndrome were included in the study. Participants underwent comprehensive preventive baseline examinations between 1978 and 2017. The National Death Index Plus service was used to document vital status. Baseline measures included physical examinations, fasting blood chemistry tests, personal and family medical history, resting blood pressure, anthropometry, treadmill exercise test, and electrocardiographies.

Metabolic syndrome was defined using the National Cholesterol Education Program Adult Treatment Panel-III Guidelines. The researchers operationalized fitness according to the duration of a maximal treadmill exercise test using a modified Balke protocol. Based on the treadmill test, the participants were categorized as “fit” (n=1208) or “unfit” (n=590) if they fell within the upper 80% or lower 20% of the age-standardized fitness distribution.

A proportional hazards regression model was used to estimate age- and smoking-adjusted hazard ratio (HR). The researchers also used a Royston-Parmar model to estimate all-cause mortality HR for fit and unfit women, adjusting for smoking status and age.

Mean fitness values for fit and unfit women were 8.4 and 6.3 (P <.001), respectively. Fit women with metabolic syndrome had higher high-density lipoprotein cholesterol levels, lower body mass indices, and lower smoking rates than unfit women with metabolic syndrome (all, P <.05).

The 204 participants who passed away since baseline tended to be older and had lower fitness levels. They also showed higher systolic blood pressure, fasting glucose, and total and low-density lipoprotein-cholesterol values than those who survived the entire study period (all, P <.05). All-cause mortality rates for fit and unfit women were 6.8 and 6.9 deaths per 10,000, respectively. When comparing participants in the fit and unfit groups, the adjusted HR for all-cause mortality with metabolic syndrome was 1.36 (95% CI, 1.01-1.83).

Limitations of the study include the demographic composition of the sample of primarily well-educated and White women, which could limit the generalizability of the results.

The study authors conclude, “Fitness is a predictor of mortality in women, and physical activity can improve fitness as well as components of MetSyn.”

This article originally appeared on Endocrinology Advisor