Cardiorespiratory Fitness Is Inversely Associated With the Incidence of Metabolic Syndrome

TLDR

Few studies have examined the link between cardiorespiratory fitness and metabolic syndrome incidence, especially in women. The authors prospectively followed 9007 men and 1491 women without metabolic syndrome, measuring waist, blood pressure, lipids, glucose, and cardiorespiratory fitness via maximal treadmill test, and defined metabolic syndrome using NCEP ATP‑III criteria. During 5.7 years of follow‑up, higher cardiorespiratory fitness was associated with a significantly lower incidence of metabolic syndrome, with multivariable hazard ratios indicating a strong inverse relationship in both men and women, making low fitness a powerful independent predictor and suggesting clinicians should promote fitness for primary prevention.

Abstract

Background— Few studies have reported the relationship between cardiorespiratory fitness and metabolic syndrome incidence, particularly in women. Methods and Results— We prospectively studied 9007 men (mean±SD age, 44±9 years; body mass index, 25±3 kg/m 2 ) and 1491 women (age, 44±9 years; body mass index, 22±2 kg/m 2 ) who were free of metabolic syndrome and for whom measures of waist girth, resting blood pressure, fasting lipids, and glucose were taken during baseline and follow-up examinations. Baseline cardiorespiratory fitness was quantified as duration of a maximal treadmill test. Metabolic syndrome was defined with NCEP ATP-III criteria. During a mean follow-up of 5.7 years, 1346 men and 56 women developed metabolic syndrome. Age-adjusted incidence rates were significantly lower (linear trend, P <0.001) across incremental thirds of fitness in men and women. After further adjustment for potential confounders, multivariable hazard ratios for incident metabolic syndrome among men in the low, middle, and upper thirds of fitness, were 1.0 (referent), 0.74 (95% CI, 0.65 to 0.84), and 0.47 (95% CI, 0.40 to 0.54) (linear trend P <0.001); in women, they were 1.0 (referent), 0.80 (95% CI, 0.44 to 1.46), and 0.37 (95% CI, 0.18 to 0.80) (linear trend P =0.01), respectively. Similar patterns of significant inverse associations between fitness and metabolic syndrome incidence were seen when men were stratified on categories of body mass index, age, and number of baseline metabolic risk factors, but patterns were variable in women. Conclusions— Low cardiorespiratory fitness is a strong and independent predictor of incident metabolic syndrome in women and men. Clinicians should consider the potential benefits of greater cardiorespiratory fitness in the primary prevention of metabolic syndrome, particularly among patients who have already begun to cluster metabolic syndrome components.