The anthropometric and sociodemographic characteristics of the participants are summarized in and . The overall percentage of the metabolic syndrome in US adults, including blacks, Mexican Americans, whites, and others, was 22.8% for men and 22.6% for women as defined by the ATP III guidelines (P=.86).
Anthropometric Characteristics of the Study Sample*
Sociodemographic Characteristics of the Study Sample*
The percentage of participants with the metabolic syndrome was 13.9%, 20.8%, and 24.3%, for black, Mexican American, and white men, respectively. The percentage of men with the metabolic syndrome was higher in Mexican American and white men than in black men (P<.001 and P = .006, respectively; statistical significance set at P<.017); the difference between Mexican American and white men was not statistically significant (P=.06; statistical significance set at P<.017).
The percentage of black and white women with the metabolic syndrome was 20.9% and 22.9%, respectively, and there was no significant between–ethnic group difference (P=.10; statistical significance set at P<.017). The percentage of Mexican American women with the metabolic syndrome was significantly higher, 27.2%, than that of black and white women (P<.001 and P=.002, respectively; statistical significance set at P<.017).
The prevalence of the metabolic syndrome by 10-year age groups is presented in . Mexican American men showed the highest prevalence of the metabolic syndrome, followed by white men and then black men. Compared with that for black men, the prevalence of the metabolic syndrome for Mexican American men was significantly higher at 40, 50, 60, and 80 years or older, whereas white men showed a significantly higher prevalence at 40, 50, 70, and 80 years or older (P<.017). There were no statistically significant differences in the prevalence of the metabolic syndrome between Mexican American and white men at any age group.
The prevalence of the metabolic syndrome by age in men (A) and women (B). Statistical significance is set at P<.017. Error bars represent the 95% confidence interval, expressed as the mean±1.96 SE.
The prevalence of the metabolic syndrome for Mexican American women was highest among the 3 ethnic groups, followed by black women and then white women. Mexican American women showed a significantly higher prevalence for the 10-year age increments between 30 and 60 years compared with white women and at age 30 years compared with black women (P<.017) (). There were no statistically significant differences in the prevalence of the metabolic syndrome between black and white women at any age group.
In both sexes, the prevalence of the metabolic syndrome increased steeply after the third decade and reached a peak in men aged 50 to 70 years and in women aged 60 to 80 years.
The association between the prevalence of the metabolic syndrome and BMI, in increments of 2, is presented in . A steep rise in the prevalence of the metabolic syndrome is observed in overweight (ie, BMI ≥25 and <30) men and women.
The prevalence of the metabolic syndrome by body mass index (calculated as weight in kilograms divided by the square of height in meters) in men (A) and women (B).
Overall, 4.6%, 22.4%, and 59.6% of normal-weight, overweight, and obese men, respectively, met the metabolic syndrome diagnostic criteria. Similarly, in women, the corresponding prevalence rates were 6.2%, 28.1%, and 50.0%, respectively.
COMPONENTS OF THE METABOLIC SYNDROME
The overall relative frequency of each component of the metabolic syndrome is given in for men and in for women. Although the frequencies of abnormal components were highly variable, several patterns are evident. Black men had a significantly higher frequency of high blood pressure (35- to 64-year age group) but lower frequencies of large waist (35- to 64-year age group) and high triglyceride and low HDL cholesterol levels (35- to 64- and ≥65-year age groups) compared with the other 2 ethnic groups. Mexican American women had a significantly higher frequency of elevated triglyceride levels in the young and middle age groups and a low HDL cholesterol level in the young age group compared with the other ethnic groups. Black women had a significantly higher frequency of high blood pressure, whereas white women had a significantly lower frequency of large waist circumference in the young and middle age groups compared with other ethnic groups.
Prevalence of Each Metabolic Syndrome Component in Men*
Prevalence of Each Metabolic Syndrome Component in Women*
The percentage of participants with each component of the metabolic syndrome who presented with the abnormality in isolated form is summarized in for men and in for women. In the 35- to 64-year age group, isolated high blood pressure was relatively frequent in black men (19.7%) compared with other isolated components (<10.0%). The proportion of individuals with a large waist was relatively high in the comparably aged women relative to other isolated components.
MULTIPLE LOGISTIC REGRESSION MODELS
Two multiple logistic regression models with the same covariates, except for age, are given in . Age in model 1 was divided into 3 categories: young, middle aged, and old. Age in model 2 was considered as a continuous variable. After adjusting for age in model 2, BMI, lifestyle-related factors, and socioeconomic status, blacks still showed a significantly lower OR for the metabolic syndrome compared with white men and women. Mexican Americans showed a significantly higher OR only in women. Significantly higher ORs were present in the 35- to 64-year and 65 years and older age groups compared with the 20- to 34-year age group in men and women as derived from model 1 with the same covariates. The ORs were 2.8 and 2.4 in the 35- to 64-year age group and 5.8 and 4.9 in those 65 years and older in men and women, respectively.
Multivariable Adjusted ORs for the Metabolic Syndrome
The ORs for the metabolic syndrome in the over-weight group relative to the normal-weight group were 5.2 for men and 5.4 for women. The ORs sharply increased to 25.2 and 67.7 for men and 14.0 and 34.5 for women when BMI was 30 to 34.9 and 35 or greater, re-spectively. When both sexes are modeled together using multiple logistic regression, the ORs for the interaction of BMI and sex were significant at BMI 30 to 34.9 (P<.001) and 35 or greater (P<.01).
Currently smoking men and women were at significantly higher risk of having the metabolic syndrome. In men, the ORs were significantly higher in the high carbohydrate intake and physical inactivity groups. In women, significantly higher ORs were observed in previous smokers, nondrinkers, and those with a low house-hold income or who were postmenopausal. Women who were heavy alcohol consumers showed a significantly lower OR than women in the slight or moderate alcohol-consuming group.