Associations of Physical Activity With Inflammatory Factors, Adipocytokines, and Metabolic Syndrome in Middle-Aged and Older Chinese People
Background— Inflammatory factors, adipocytokines, and the metabolic syndrome are important determinants of cardiometabolic disease. It remains unclear how physical activity is related to these risk factors. Our objective was to investigate single and joint associations of physical activity with inflammatory factors, adipocytokines, and the metabolic syndrome among middle-aged and older Chinese people.
Methods and Results— A total of 3289 individuals (1458 men, 1831 women) 50 to 70 years of age participated in a population-based cross-sectional survey in Beijing and Shanghai, China. Levels of total physical activity were assessed with the International Physical Activity Questionnaire. High-sensitivity C-reactive protein, interleukin-6, tumor necrosis factor-α receptor 2, adiponectin, and retinol-binding protein 4 were measured. The metabolic syndrome was defined using the updated National Cholesterol Education Program/Adult Treatment Panel III criteria for Asian Americans. Plasma concentrations of high-sensitivity C-reactive protein were 1.58, 1.74, and 1.27 mg/L (P=0.0138) and of adiponectin were 16.12, 16.20, and 17.21 mg/L (P=0.0078) among individuals with low, medium, and high levels of total physical activity, respectively, with adjustment for potential confounders. In the multivariable-adjusted logistic regression analyses, participants with higher levels of total physical activity had a lower risk of having the metabolic syndrome (odds ratio, 0.68; 95% confidence interval, 0.54 to 0.85; P for trend=0.001) compared with those with lower levels.
Conclusions— Being physically active is associated with a better profile of inflammatory factors and adipocytokines and a reduced risk of having the metabolic syndrome among Chinese people.
Received November 5, 2008; accepted April 17, 2009.
Inflammatory factors, adipocytokines, and the metabolic syndrome (MetS) play important roles in the origin of cardiometabolic diseases, including cardiovascular disease (CVD) and type 2 diabetes mellitus.1–4 Low-grade systemic inflammation is associated with the initiation and severity of atherosclerotic CVD and the development of metabolic disorders. Elevated proinflammatory cytokines such as interleukin (IL)-6 and tumor necrosis factor (TNF)-α stimulate the hepatic synthesis of C-reactive protein (CRP), an acute-phase reactant and a sensitive indicator of systemic inflammation, playing a substantial role in the pathogenesis of atherosclerosis2 and insulin resistance.4 Adiponectin, secreted predominantly by adipocytes is the only adipocytokine that is inversely associated with metabolic and cardiovascular disorders.3 On the other hand, retinol-binding protein 4 (RBP4), a newly identified adipocytokine, has been found to be positively associated with the MetS and its components.5,6 Although inflammatory factors and adipocytokines have different pathophysiological pathways and targeted tissues and organs, the altered systemic balance of inflammatory factors and adipocytokines may result in a common antecedent of cardiometabolic disease called the MetS, a constellation of cardiometabolic risk factors, including altered glucose metabolism, dyslipidemia, and hypertension, associated with an increased risk for both CVD and type 2 diabetes mellitus.1
Clinical Perspective on p 2977
Physical activity is recommended as a key lifestyle factor in the prevention and treatment of type 2 diabetes mellitus and CVD.7,8 We have previously reported that CRP,9 adiponectin,10 and RBP46 are closely associated with the risk for the MetS among people 50 to 70 years of age in China. However, little is known about how physical activity influences these risk factors in this population. The aim of the present study was to investigate the associations of physical activity with inflammatory factors, adipocytokines, and the MetS among the study participants.
The Nutrition and Health of Ageing Population in China Study is a population-based cross-sectional study among noninstitutionalized Chinese people 50 to 70 years of age in Beijing and Shanghai, China. It has been described in detail previously.9,11 In brief, the fieldwork was conducted simultaneously in the 2 municipalities from March to June 2005. A multistage sampling method was used to recruit the study participants. In each city, 2 urban districts and 1 rural district were chosen to represent a range of socioeconomic groups. In the sampling process, the plan was to randomly select 400 participants from each urban district and 800 persons from each rural district from the eligible candidates listed in the residential registration record. All participants provided written informed consent. The protocol was approved by the institutional review board of the Institute for Nutritional Sciences. The present analysis comprised 3289 eligible participants (1458 men, 1831 women).11
A home interview was conducted by trained physicians or public health workers from the local Centers for Disease Control and Prevention and community hospitals. Information on demographic factors, health status, health behavior, and physical activity was collected with a standardized questionnaire. All participants were invited to have a physical examination at the local health station or the community clinic after the home interview. Participants were asked to fast overnight. Fasting peripheral venous EDTA blood samples were collected and centrifuged at 4°C and 3000 rpm for 15 minutes. After being frozen, the samples were shipped in dry ice to the Institute for Nutritional Sciences and stored at −80°C until analysis.
Assessment of Physical Activity and Covariates
We used the short form of the International Physical Activity Questionnaire (IPAQ) to estimate the participants’ levels of physical activity by adding questions on frequency and duration of low-intensity activity (ie, home activities, including food preparation, home/yard cleaning, and child care). For evaluation of total physical activity, separate metabolic equivalent (MET) hours per week were calculated for low, moderate, and vigorous activities and walking according to the following formulas12: MET coefficient of activity×duration (hour)×frequency (day). The corresponding MET coefficients were 2.5, 4.0, 8.0, and 3.3, respectively (1 MET is defined as metabolic expenditure at rest).12 Total physical activity levels were assessed by combining each of the separate scores. Levels of total physical activity, low-intensity activity, and walking were categorized as low, medium, and high by the corresponding approximate tertiles. The cutoff points were ≤77.4, >77.4 to ≤137.8, and >137.8 MET-h/wk for total physical activity; ≤25.0, >25.0 to ≤50.0, and >50.0 MET-h/wk for low-intensity activity; and ≤11.6, >11.6 to ≤34.7, and >34.7 MET-h/wk for walking, respectively. Variables on moderate- and vigorous-intensity activities were grouped as yes or no.
Educational attainment was categorized as low (0 to 6 years), medium (7 to 9 years), and high (≥10 years). According to the respondents’ self-reported smoking status, participants were grouped as current smokers, ex-smokers, and nonsmokers. These variables were dichotomized as yes or no on the basis of the responses to questions on alcohol drinking; use of antihypertensive drugs, aspirin, and antibiotics; coronary heart disease (CHD); stroke; and family history of CVD and diabetes mellitus.
Measurements of weight, height, waist circumference, and blood pressure have been described previously.9,11 Body mass index was calculated as weight in kilograms divided by height in meters squared.
Plasma fasting glucose, total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein cholesterol, and triglycerides were measured enzymatically on an automatic analyzer (Hitachi 7080, Tokyo, Japan) with reagents from Wako Pure Chemical Industries (Osaka, Japan). Fasting insulin was determined by radioimmunoassay (Linco Research, St Charles, Mo). Plasma high-sensitivity CRP (hsCRP) concentration was determined by a particle-enhanced immunoturbidimetric assay (Ultrasensitive CRP kit, Orion Diagnostica, Espoo, Finland).9 The lower detection limit of the assay was 0.25 mg/L. Undetectable hsCRP values were recorded as 0.12 mg/L.9 IL-6 was measured with a high-sensitivity ELISA (Quantikine HS IL-6 Immunoassay, R&D Systems, Inc, Minneapolis, Minn).13 Soluble fraction of TNF-α receptor 2 (TNF-α-R2) was detected with Human Death Receptor 3-Plex kit (Biosource International, Inc, Camarillo, Calif) through the Multiplex Suspension Array System (Bio-Plex System) with Bio-Plex Manager 4.0 (Bio-Rad Laboratories, Inc, Hercules, Calif).13 Plasma adiponectin concentrations were measured by Luminex xMAP Technology on a Bio-Rad Multiplex Suspension Array System.10 Human RBP4 was measured in duplicate by a sandwich ELISA developed in-house.6
Definition of Metabolic Syndrome
The MetS was defined using the updated National Cholesterol Education Program/Adult Treatment Panel III criteria for Asian Americans as having ≥3 of the following components: waist circumference ≥90 cm for men or ≥80 cm for women; triglycerides ≥1.7 mmol/L; HDL cholesterol <1.03 mmol/L for men or <1.30 mmol/L for women; blood pressure ≥130/85 mm Hg or current use of antihypertensive medications; or fasting glucose ≥5.6 mmol/L, type 2 diabetes mellitus previously diagnosed by a physician, or current use of antidiabetic medications.14
Differences in the variables by different levels and types of physical activity were assessed by either a general linear regression model for continuous variables or a logistic regression model for categorical variables. Spearman partial correlation coefficients between total physical activity, inflammatory factors, adipocytokines, and MetS components were computed with adjustment for age, sex, and investigation site. We constructed mean SD scores (z scores)15 of inflammatory factors and adipocytokines for subjects with complete data (n=3197 for inflammatory factors, n=3161 for adipocytokines). The inflammatory factor and adipocytokine z scores were computed as follows: (hsCRP z score+IL-6 z score+TNF-α-R2 z score)/3 and (adiponectin z score×(−1)+RBP4 z score)/2, respectively. High inflammatory factor and adipocytokine z scores were defined as being in the top quartile. The corresponding cutoff points were 0.429 for inflammatory factor z score and 0.470 for adipocytokine z score. We computed the simple and multivariable adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the MetS, its components, and high inflammatory factor and adipocytokine z scores with the logistic regression model. Potential confounding factors as suggested by previous studies were controlled for in the multivariable analyses. In addition, inflammatory factors and adipocytokines were further adjusted in the multivariable model to test whether the detected association was independent of these factors. When appropriate, the ln-transformed value was used to minimize the skewness of the distribution of inflammatory factors, adipocytokines, and triglycerides. Excluding those with CHD (n=227), stroke (n=133), or diabetes mellitus (n=447) and those with an hsCRP concentration >10 mg/L (n=38) yielded a similar pattern of results. We therefore report the results for the entire sample. Statistical inference was made for values of P<0.05 (2 sided). The statistical analyses were performed with Stata version 9.2 (Stata Corp, College Station, Tex).
The authors had full access to and take full responsibility for the integrity of the data. All authors have read and agree to the manuscript as written.
Characteristics of the Population
Individuals with high levels of total physical activity were younger and less educated than those with low or medium levels (Table 1). They also were more likely to be cigarette smokers, less likely to use antihypertensive drugs or aspirin, and less likely to have the MetS, diabetes mellitus, CHD, or a stroke. Furthermore, those with high levels of activity had relatively lower body mass index, waist circumference, diastolic blood pressure, low-density lipoprotein cholesterol, triglycerides, fasting glucose, insulin, hsCRP, and adipocytokine z score but higher levels of HDL cholesterol and adiponectin (Table 1).
Associations of Physical Activity With Inflammatory Factors, Adipocytokines, and MetS
Total physical activity was inversely correlated with hsCRP, waist circumference, and triglycerides and positively correlated with adiponectin and HDL cholesterol after adjustment for age, sex, and investigation site (Table I of the online-only Data Supplement).
For inflammatory factors and adipocytokines, high levels of total physical activity were associated with lower levels of hsCRP (P=0.0078) and higher levels of adiponectin (P=0.0138) after multivariable adjustment (including age; sex; investigation site; body mass index; education; smoking; alcohol drinking; high blood pressure; use of antihypertensive drug, aspirin, and antibiotics; and other covariates) (Table 2). Engagement in vigorous- and moderate-intensity activities was associated with lower levels of hsCRP. The inverse association between moderate-intensity activity and hsCRP remained statistically significant after the exclusion of those who engaged in vigorous-intensity activity (geometric mean, 0.69 mg/L [95% CI, 0.65 to 0.73] and 0.80 mg/L [95% CI, 0.75 to 0.85] for those with and without moderate-intensity activity, respectively). Engagement in vigorous-intensity activity was associated with lower levels of RBP4 (P=0.0198). Relatively higher levels of light-intensity activity and walking were associated with lower levels of TNF-α-R2.
After adjustment for age, sex, and investigation site, individuals with a high level of total physical activity had a lower risk of having the MetS (OR, 0.61; 95% CI, 0.50 to 0.74; P for trend <0.0001). Those who engaged in vigorous- and moderate-intensity activities were less likely to have the MetS (Table 3).
In the multivariable-adjusted analyses (model 2), high levels of total physical activity and vigorous- and moderate-intensity activities remained significantly associated with lower risk of having the MetS. The corresponding ORs were 0.65 (95% CI, 0.52 to 0.80; P for trend <0.0001), 0.75 (95% CI, 0.59 to 0.96), and 0.81 (95% CI, 0.68 to 0.97), respectively. Further controlling for inflammatory factors and adipocytokines only slightly attenuated the strength of the association for total physical activity (OR, 0.68; 95% CI, 0.54 to 0.85; P for trend=0.001).
Joint Associations of Total Physical Activity, Inflammatory Factors, Adipocytokines, and MetS
Among individuals with higher levels of inflammatory factors and adipocytokines (top quartile of z score), those with high levels of total physical activity were ≈35% less likely to have the MetS than those with low to medium levels of total physical activity (Figure 1A and 1B). Similarly, among individuals with and without the MetS, those with high levels of total physical activity were less likely to have adverse levels of inflammatory factors and adipocytokines than those with low to medium levels of total physical activity (Figure 1C and 1D).
The inverse association between high levels of total physical activity and risk for the MetS in the multivariable-adjusted models was consistent across subgroups among our study participants with only a few exceptions (Figure 2). The association seemed to be more pronounced for men than women (P for interaction=0.0389).
In multivariable analyses with both sexes combined (model 2), individuals with high levels of total physical activity had lower risks of abdominal obesity (OR, 0.79; 95% CI, 0.64 to 0.97) and hypertriglyceridemia (OR, 0.60; 95% CI, 0.47 to 0.76) and low HDL cholesterol (OR, 0.80; 95% CI, 0.66 to 0.99) compared with those with low levels. When the analyses were further controlled for inflammatory factors and adipocytokines, the significantly inverse association remained for triglycerides only.
We found that high levels of physical activity were associated with lower levels of hsCRP and higher levels of adiponectin, in addition to a lower risk for the MetS. Moderate- to vigorous-intensity activities showed stronger associations than other activities. This appeared to also be the case for individuals at high levels of cardiometabolic risk. To the best of our knowledge, this is the first study to simultaneously investigate single and joint associations of physical activity, inflammatory factors, adipocytokines, and the MetS.
Studies have consistently shown an inverse relationship between physical activity and markers of inflammation, especially for CRP. North Americans who frequently engaged in physical activity had significantly lower CRP compared with those who were physically inactive.16 In the Women’s Health Study, women who had lower levels of physical activity had higher odds of having CRP >3 mg/L. In the British Regional Heart Study, after a 20-year follow-up, those who were inactive at baseline but later participated in light physical activity had CRP levels that approached those observed in participants who had remained active throughout the follow-up period.17 A few studies have reported the associations between physical activity and adipocytokines. Among 24 obese adults who completed a 26-week lifestyle modification program, adiponectin increased significantly in 8 individuals with type 2 diabetes mellitus.18 In a cross-sectional analysis including 120 adolescents, higher levels of vigorous-intensity activity were associated with higher adiponectin levels.19 A study in 60 white men and women found that RBP4 was significantly decreased in those with improved insulin sensitivity after 1 month of exercise training.5 Similarly, in obese children, RBP4 levels were reduced remarkably after a 3-month physical activity–based lifestyle intervention.20
Several studies in different population groups have reported that physical activity is associated with a reduced risk of the MetS. In the China National Nutrition and Health Survey 2002, individuals who were active or very active were 40% less likely to have the MetS compared with those who were sedentary.21 In the UK Whitehall II study, both vigorous and moderate leisure-time physical activities were associated with a reduced risk of having the MetS.22 In a Finnish cohort study, baseline total leisure-time physical activity was inversely associated with the risk of developing the MetS during a 4-year follow-up.23
Interestingly, high levels of physical activity are associated with less likelihood of having the MetS even among individuals with adverse levels of inflammatory factors or adipocytokines. We have previously reported that adverse levels of hsCRP,9 adiponectin,10 and RBP46 are closely associated with increased risks for the MetS. These results indicate that being physically active might reduce, to some extent, the levels of cardiometabolic risk even among individuals at high risk.
The biological mechanisms of physical activity influencing inflammatory factors, adipocytokines, and the MetS have not been fully elucidated. Physical activity reduces abdominal obesity24 and triglyceride levels and increases HDL cholesterol.24,25 However, the association between physical activity and abdominal obesity was not statistically significant after further controlling for inflammatory factors and adipocytokines in the multivariable regression analyses. Waist circumference was correlated with all inflammatory factors and adipocytokines (Table I of the online-only Data Supplement). Abdominal obesity is an indicator of visceral fat accumulation, which is the major source of proinflammatory factors and adiocytokines.26 Simultaneous adjustment for these factors might lead to attenuation of this association. Although we cannot make any causal inference from a set of correlated variables from a cross-sectional study, this result supports the central role of visceral fat accumulation in the pathogenesis of the MetS.
The effects of physical activity on decreasing systemic inflammation are likely to result from multiple mechanisms.27–29 Physical activity may simultaneously decrease TNF-α and IL-6.29 TNF-α induces the production of IL-6, which stimulates the acute-phase response in liver.30 Moreover, TNF-α may induce downregulation of adiponectin,3 which regulates glucose and lipid metabolism by targeting the liver and skeletal muscle exerting antiinflammatory, antiatherogentic, and antidiabetic effects.26 Meanwhile, physical activity is associated with the upregulation of antiinflammatory cytokines (eg, IL-1ra and IL-10).28,29 It also may improve endothelial function and insulin sensitivity and exert an antioxidant effect.27 Whether RBP4 might be affected by physical activity through improved insulin sensitivity warrants further investigation.
In this study, we used the IPAQ short format (last 7 days) to assess the participants’ physical activity and added questions on the frequency and duration of light-intensity activities, considering the relatively older age of our study participants. The IPAQ has been demonstrated to be a valid and reliable tool for assessing physical activity among the Chinese elderly.31 However, given the cross-sectional nature of the study design, our results might not reflect causal associations. Individuals with diagnosed health abnormalities, eg, hypertension and dyslipidemia, might change their behavior toward a healthy lifestyle as a result of their diagnosis. However, this would not explain the inverse association between physical activity and the MetS observed in this study.
The association between physical activity and the risk of the MetS was weaker in women than in men (Figure 2). Women were less likely to engage in moderate- and vigorous-intensity activities than men (moderate-intensity activity, 52.0% versus 65.1%; vigorous-intensity activity, 14.6% versus 23.6%; all P<0.0001). The cutoff point of high versus medium to low levels of total physical activity was ≈138 MET-h/wk, which translates to ≈2.5 hours of vigorous activities per day. This amount is higher than the current recommendation, ie, 30 minutes on most days of the week.32 About half of our study participants were recruited from the rural area. The survey was conducted during the season when the farmers begin their farming activities. Hence, the distribution of physical activity in our study population might be higher in the rural area as a result of this seasonal variation. In this regard, we carried out a posthoc analysis among those who reported no vigorous-intensity activity. We found that individuals who engaged in moderate-intensity activity had a 0.14 U (ln-transformed values) lower level of hsCRP compared with those who did not, which corresponded to a 6% risk reduction for the MetS in the multivariable analysis (model 3; OR, 0.94; 95% CI, 0.92 to 0.95). This suggests that moderate-intensity activity might provide relevant health benefits with respect to the development of metabolic disorders in our study population.
High levels of physical activity are associated with a better profile of inflammatory factors and adipocytokines and a lower risk of the MetS in middle-aged and older Chinese people. To explore the appropriate types and levels of physical activity for prevention of cardiometabolic disease among Chinese populations, a prospective study is warranted. Public health recommendations to promote moderate- to vigorous-intensity activities among middle-aged and older Chinese people may help to curtail the current epidemic of cardiometabolic disease in China.
We are grateful to Ying Wu, Liang Sun, Shaojie Ma, and He Zheng for their kind help at various stages of this study.
Sources of Funding
This study was supported financially by the Chief Scientist Program of Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences (SIBS2008006); the Ministry of Science and Technology of China (973 Program, grant 2006CB503900; International Collaboration Program, grant 2008DFA31960); the Chinese Academy of Sciences (The Knowledge Innovation Program, grant KSCX1-YW-02); the Shanghai-Unilever Research Development Fund (grant 200306); and Unilever Corporate Research, UK (grant CH-2006–0941). The sponsors were not involved in the study design, data collection, analysis, or interpretation.
Ford ES. Risks for all-cause mortality, cardiovascular disease, and diabetes associated with the metabolic syndrome: a summary of the evidence. Diabetes Care. 2005; 28: 1769–1778.
Libby P, Ridker PM, Maseri A. Inflammation and atherosclerosis. Circulation. 2002; 105: 1135–1143.
Pickup JC. Inflammation and activated innate immunity in the pathogenesis of type 2 diabetes. Diabetes Care. 2004; 27: 813–823.
Diabetes Prevention Program Research Group. Intensive lifestyle intervention or metformin on inflammation and coagulation in participants with impaired glucose tolerance. Diabetes. 2005; 54: 1566–1572.
Thompson PD, Buchner D, Pina IL, Balady GJ, Williams MA, Marcus BH, Berra K, Blair SN, Costa F, Franklin B, Fletcher GF, Gordon NF, Pate RR, Rodriguez BL, Yancey AK, Wenger NK. Exercise and physical activity in the prevention and treatment of atherosclerotic cardiovascular disease: a statement from the Council on Clinical Cardiology (Subcommittee on Exercise, Rehabilitation, and Prevention) and the Council on Nutrition, Physical Activity, and Metabolism (Subcommittee on Physical Activity). Circulation. 2003; 107: 3109–3116.
Guidelines for data processing and analysis of the International Physical Activity Questionnaire (IPAQ). Available at: http://www.ipaq.ki.se/scoring.pdf. Accessed October 1, 2008.
Grundy SM, Cleeman JI, Daniels SR, Donato KA, Eckel RH, Franklin BA, Gordon DJ, Krauss RM, Savage PJ, Smith SC Jr, Spertus JA, Costa F. Diagnosis and management of the metabolic syndrome: an American Heart Association/National Heart, Lung, and Blood Institute Scientific Statement. Circulation. 2005; 112: 2735–2752.
Yudkin JS, Stehouwer CDA, Emeis JJ, Coppack SW. C-reactive protein in healthy subjects: associations with obesity, insulin resistance, and endothelial dysfunction: a potential role for cytokines originating from adipose tissue? Arterioscler Thromb Vasc Biol. 1999; 19: 972–978.
Wannamethee SG, Lowe GDO, Whincup PH, Rumley A, Walker M, Lennon L. Physical activity and hemostatic and inflammatory variables in elderly men. Circulation. 2002; 105: 1785–1790.
Rennie KL, McCarthy N, Yazdgerdi S, Marmot M, Brunner E. Association of the metabolic syndrome with both vigorous and moderate physical activity. Int J Epidemiol. 2003; 32: 600–606.
Laaksonen DE, Lakka HM, Salonen JT, Niskanen LK, Rauramaa R, Lakka TA. Low levels of leisure-time physical activity and cardiorespiratory fitness predict development of the metabolic syndrome. Diabetes Care. 2002; 25: 1612–1618.
Orchard TJ, Temprosa M, Goldberg R, Haffner S, Ratner R, Marcovina S, Fowler S, for the Diabetes Prevention Program Research Group. The effect of metformin and intensive lifestyle intervention on the metabolic syndrome: the Diabetes Prevention Program Randomized Trial. Ann Intern Med. 2005; 142: 611–619.
Hajer GR, van Haeften TW, Visseren FL. Adipose tissue dysfunction in obesity, diabetes, and vascular diseases. Eur Heart J. 2008; 29: 2959–2971.
Heinrich PC, Castell JV, Andus T. Interleukin-6 and the acute phase response. Biochem J. 1990; 265: 621–636.
Pate RR, Pratt M, Blair SN, Haskell WL, Macera CA, Bouchard C, Buchner D, Ettinger W, Heath GW, King AC. Physical activity and public health: a recommendation from the Centers for Disease Control and Prevention and the American College of Sports Medicine. JAMA. 1995; 273: 402–407.
Inflammatory factors, adipocytokines, and the metabolic syndrome are important determinants of cardiometabolic disease. It remains unknown whether physical activity, a key modifiable factor for cardiometabolic disease control and prevention, may modify these cardiovascular risk factors. We analyzed single and joint associations of physical activity, inflammatory factors, adipocytokines, and the metabolic syndrome among 3289 Chinese people 50 to 70 years of age who participated in a cross-sectional survey in Beijing and Shanghai in 2005. Levels of total physical activity were assessed with the International Physical Activity Questionnaire. Inflammatory factors (high-sensitivity C-reactive protein, interleukin-6, and tumor necrosis factor-α receptor 2) and adipocytokines (adiponectin and retinol-binding protein 4) were measured. The metabolic syndrome was defined according to the National Cholesterol Education Program/Adult Treatment Panel III criteria for Asian Americans. In multivariable regression analyses, high levels of total physical activity were significantly associated with a 20% lower level of high-sensitivity C-reactive protein, 7% higher level of adiponectin, and 30% lower risk of having the metabolic syndrome compared with those with low levels. Importantly, higher levels of physical activity were associated with a lower likelihood of having the metabolic syndrome even among individuals with adverse levels of inflammatory factors or adipocytokines. Even moderate-intensity activities were related to the health benefits. Public health recommendations to promote moderate- to vigorous-intensity activities may help to curtail the current epidemic of cardiometabolic disorders in Chinese people.
Guest Editor for this article was Robert H. Eckel, MD.
The online-only Data Supplement is available with this article at http://circ.ahajournals.org/cgi/content/full/CIRCULATIONAHA.108.833574/DC1.
Presented in part at the 68th Scientific Sessions of the American Diabetes Association, San Francisco, Calif, June 6–10, 2008.