The metabolic syndrome is a cluster of abnormalities that are associated with increased risk of developing CVD and type 2 diabetes (5
). Results of this study show that a 6-month lifestyle intervention of moderate weight loss and low-intensity exercise effectively reduces both CVD risk factors and the prevalence of the MetSyn by 45%. A novel outcome of our study is that the reductions in TG, glucose, and blood pressure are the MetSyn criteria primarily associated with conversion from MetSyn to non-MetSyn status. This is similar to National Health and Nutrition Examination Survey study data which suggests that hypertriglyceridemia and hypertension are the cardiometabolic abnormalities responsible for the heightened prevalence of MetSyn among older women (3
) and supports the possibility that the high prevalence of MetSyn is related to weight gain in midlife (23
) leading to abdominal obesity, high TGs, and low high-density lipoprotein (24
). Our results also show that WL+LEX reduces the constituents of the MetSyn in obese postmenopausal women both with and without MetSyn to an equivalent degree, which suggests that this intervention may be effective in preventing as well as reversing the MetSyn. Although most of the MetSyn variables decreased in response to the intervention, there were greater reductions in the non-MetSyn criteria of total cholesterol and low-density lipoprotein cholesterol, IL-6, and VAT in the non-MetSyn than in the MetSyn participants, suggesting an overall health benefit of this lifestyle intervention for obese postmenopausal women.
Interestingly, none of the changes in MetSyn variables after WL+LEX differed between R and NR when analyzed as continuous variables. Although MetSyn is predictive of the development of diabetes and CVD, both the American and the European Diabetes Associations and others express concern over the arbitrary and dichotomous nature of the cut points for its constituents (25
), which is supported by the discordance between the categorical and continuous variable analysis in this study.
The participants who achieved larger reductions in percent body fat and fat mass with WL+LEX were more likely to reverse MetSyn status. The small change in VO2max
, when calculated as absolute O2
consumption (liters per minute) to minimize the inflated increase in VO2max
if expressed per kilogram body weight, supports the primary role of WL in resolution of MetSyn. However, the exercise may have prevented significant loss of lean mass seen with WL alone in older people, which may predispose to sarcopenia (29
). Thus, both WL and meeting the physical activity guidelines for Americans seem to reduce the incidence and development of MetSyn components in older adults (30
). The moderate dropout rate and resultant small sample size probably precluded determination whether the resolution of the MetSyn in these women is related primarily to the decrease in visceral body fat. Although there was no difference in the attendance to the WL+LEX classes between the responders and the nonresponders, the responders did lose more body fat and may have complied better with the intervention suggesting that behavioral factors may be important. Other possible contributing factors to these responses include genetic susceptibility, as the effects of the fat mass and obesity associated (FTO
) gene variants on obesity can be blunted through physical activity (32
The post hoc analysis is a weakness in the design, but our results are congruent with the findings that a 6-month moderate intensity exercise regimen consisting of flexibility, balance, aerobic and strength training, and 8% weight loss is associated with a 59% reduction in the prevalence of the MetSyn in older men and women (14
). Interestingly, the 41% reduction in the prevalence of MetSyn in the Diabetes Prevention Program population of glucose intolerant men and women (13
) was observed after 3 years of a WL and exercise intervention in contrast to the 6-month intervention in the current study and that of Villareal and colleagues (14
). In another study examining the effects of a Mediterranean diet with instructions to increase daily physical activity by 30 minutes, there was a 60% reduction in the MetSyn in middle-aged men and women after 2 years (33
). In a recent study (34
), there were even greater reductions in MetSyn variables after a more intensive walking program in which energy intake is kept constant or when exercise is combined with caloric restriction to increase VO2max
by ~15% in a smaller group of 24 older men and women with MetSyn. Furthermore, in an observational study in older Japanese men and women, the risk of MetSyn was 4.3 times greater in the least active quartile compared with the most active (35
). This suggests that the intensity, duration, and likelihood of compliance to the lifestyle intervention should be considered when designing treatment program for MetSyn.
Several investigators postulate that a chronic low-grade inflammation is a key component of MetSyn in older people (36
), especially given the relationship between elevated cytokine concentrations, obesity, and insulin resistance (37
). However, inflammation is not included in the definition of the MetSyn in the United States (1
) or Europe (38
). Similar to our previous work, there are no differences in the majority of the cytokine concentrations at baseline other than soluble tumor necrosis factor receptor (sTNFR1A) between the MetSyn and the non-MetSyn groups (40
). There were significant reductions in both high-sensitive C-reactive protein and TNF-α levels in the MetSyn and IL-6 in the non-MetSyn participants, confirming our earlier reports (36
). Contrary to the reductions found in response to a 12-month Mediterranean diet and physical activity intervention (33
), IL-6 increased significantly in the MetSyn and NR groups. Although we anticipated a decrease in sTNFR1A, but not in sTNFR1B receptors based on our prior work (41
), there were only small decreases in TNF receptors with intervention. It is possible that the low-intensity walking exercise chosen in the current study did not improve fitness to the same extent as in our previous interventions, given the inverse relationship of the changes in sTNFR1A with VO2max
). Further research in a larger sample is necessary to assess the independent and combined effects of weight loss and aerobic exercise of different intensities and duration on cytokines, and their role in the CVD risk and complications associated with MetSyn in older adults.
Thus, a lifestyle intervention that employs a weight-reducing diet coupled with low-intensity exercise reduces the constituents of the MetSyn in overweight and obese middle-aged to older Caucasian and African American postmenopausal women. This intervention is effective in women with and without MetSyn, suggesting a beneficial role for WL+LEX in preventing the development of MetSyn as well as treating MetSyn in these high CVD risk individuals. Future studies are necessary to elucidate the mechanisms underlying these metabolic changes, the most effective exercise and weight loss programs and the predictors of the most desirable metabolic and health-related outcomes in older women with MetSyn.