Body mass index, waist circumference, and health risk: evidence in support of current National Institutes of Health guidelines.
BACKGROUND
No evidence supports the waist circumference (WC) cutoff points recommended by the National Institutes of Health to identify subjects at increased health risk within the various body mass index (BMI; calculated as weight in kilograms divided by the square of height in meters) categories.


OBJECTIVE
To examine whether the prevalence of hypertension, type 2 diabetes mellitus, dyslipidemia, and the metabolic syndrome is greater in individuals with high compared with normal WC values within the same BMI category.


METHODS
The subjects consisted of 14 924 adult participants of the Third National Health and Nutrition Examination Survey, which is a nationally representative cross-sectional survey. Subjects were grouped by BMI and WC in accordance with the National Institutes of Health cutoff points. Within the normal-weight (18.5-24.9), overweight (25.0-29.9), and class I obese (30.0-34.9) BMI categories, we computed odds ratios for hypertension, diabetes, dyslipidemia, and the metabolic syndrome and compared subjects in the high-risk (men, >102 cm; women, >88 cm) and normal-risk (men, <or=102 cm; women, <or=88 cm) WC categories.


RESULTS
With few exceptions, within the 3 BMI categories, those with high WC values were increasingly likely to have hypertension, diabetes, dyslipidemia, and the metabolic syndrome compared with those with normal WC values. Many of these associations remained significant after adjusting for the confounding variables (age, race, poverty-income ratio, physical activity, smoking, and alcohol intake) in normal-weight, overweight, and class I obese women and overweight men.


CONCLUSIONS
The National Institutes of Health cutoff points for WC help to identify those at increased health risk within the normal-weight, overweight, and class I obese BMI categories.
Janssen
Ian
I
School of Physical and Health Education, Queen's University, Kingston, Ontario, Canada K7L 3N6.
Katzmarzyk
Peter T
PT
Ross
Robert
R
D000328:Adult; D000368:Aged; D001824:Body Constitution; D015992:Body Mass Index; D001835:Body Weight; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology / Q000209:etiology*; D019317:Evidence-Based Medicine; D005260:Female; D006801:Humans; D006949:Hyperlipidemias / Q000453:epidemiology / Q000209:etiology*; D006973:Hypertension / Q000453:epidemiology / Q000209:etiology*; D016015:Logistic Models; D008297:Male; D024821:Metabolic Syndrome / Q000453:epidemiology / Q000209:etiology*; D008875:Middle Aged; D009316:National Institutes of Health (U.S.); D009765:Obesity / Q000150:complications* / Q000453:epidemiology; D016017:Odds Ratio; D017410:Practice Guidelines as Topic; D012307:Risk Factors; D012720:Severity of Illness Index; D014481:United States / Q000453:epidemiology