Helicobacter pylori and overweight status in the United States: data from the Third National Health and Nutrition Examination Survey

Obesity is an important public health problem in the United States. Because of its potential effects on gastric leptin homeostasis, Helicobacter pylori may play a role in regulating body weight. The authors' aim in this study was to examine the association between H. pylori colonization and overweight status. Nonpregnant participants in the Third National Health and Nutrition Examination Survey (1988-1994) aged > or = 20 years who had had H. pylori testing performed and body mass index (weight (kg)/height (m2)) measured were studied. Overweight was defined as a body mass index greater than or equal to 25. On the basis of serologic results, the participants were categorized into three H. pylori status groups: H. pylori-positive and cytotoxin-associated gene A (cagA)-positive (H. pylori+ cagA+), H. pylori-positive and cagA-negative (H. pylori+ cagA-), and H. pylori-negative (H. pylori-). Of the 7,003 subjects with complete body mass index and H. pylori data, 2,634 (weighted percentage, 22.9%) were H. pylori+ cagA+, 1,385 (15.1%) were H. pylori+ cagA-, and 2,984 (62.0%) were H. pylori-. The adjusted odds of being overweight were 1.17 (95% confidence interval: 0.98, 1.39; p = 0.075) for the H. pylori+ cagA+ group and 0.99 (95% confidence interval: 0.80, 1.22; p = 0.92) for the H. pylori+ cagA- group in comparison with H. pylori- subjects. Serum leptin levels did not differ significantly between the three H. pylori groups. In this US population-based study, there was no significant association between H. pylori colonization, cagA+ strains of H. pylori, and being overweight.     

Hepatitis A virus infection in the United States: serologic results from the Third National Health and Nutrition Examination Survey

To determine the prevalence of hepatitis A virus (HAV) infection in the general U.S. population, sera from participants in the Third National Health and Nutrition Examination Survey (NHANES III) conducted in 1988–1994 were tested for antibody to HAV (anti-HAV). Among 21,260 participants aged ≥6 years tested, the overall prevalence of infection was 31.3%, and increased markedly with age. The age-adjusted prevalence was significantly higher among foreign- compared to U.S.-born participants, and was highest among Mexican-Americans and lowest among non-Hispanic whites. Among U.S.-born children, only Mexican-American ethnicity and income below the poverty level were associated with HAV infection in a multivariate model. During this period before hepatitis A vaccination, age, ethnicity and birthplace were the most important determinants of HAV infection in the United States.     

Serum vitamin C concentrations and diabetes: findings from the Third National Health and Nutrition Examination Survey, 1988-1994.

BACKGROUND: Previous studies suggested that diabetes mellitus may lower serum vitamin C concentrations, but most of these studies used clinic-based populations with established diabetes of varying duration and did not adjust for important covariates. OBJECTIVE: Using a population-based sample and adjusting for important covariates, we asked whether serum vitamin C concentrations in persons with newly diagnosed diabetes differed from those in persons without diabetes. DESIGN: Data were obtained from the third National Health and Nutrition Examination Survey (1988-1994). Serum vitamin C was assayed by using reversed-phase HPLC with multiwavelength detection. Diabetes status (n = 237 persons with diabetes; n = 1803 persons without diabetes) was determined by oral-glucose-tolerance testing of the sample aged 40-74 y. RESULTS: After adjustment for age and sex, mean serum vitamin C concentrations were significantly lower in persons with newly diagnosed diabetes than in those without diabetes. After adjustment for dietary intake of vitamin C and other important covariates, however, mean concentrations did not differ according to diabetes status. CONCLUSION: When assessing serum vitamin C concentrations by diabetes status in the future, researchers should measure and account for all factors that influence serum vitamin C concentrations.     

Correlates of serum lutein + zeaxanthin: findings from the Third National Health and Nutrition Examination Survey

The determinants of blood levels of carotenoids were previously investigated in small or select samples. The relations of serum lutein + zeaxanthin to possible diet, lifestyle, and physiological determinants in 7059 participants of the Third National Health and Nutrition Examination Survey (1988-1994), > or = 40 y old, were examined. In a fully adjusted, multiple linear regression model, lower serum lutein + zeaxanthin was significantly associated with smoking, heavy drinking, being white, female, or not being physically active, having lower dietary lutein + zeaxanthin, higher fat-free mass, a higher percentage of fat mass, a higher waist-hip ratio, lower serum cholesterol, a higher white blood cell count, and high levels of C-reactive protein (P < 0.05). The model explained 24% of the variation present in serum lutein + zeaxanthin for the current sample. The correlation between dietary and serum lutein + zeaxanthin was 0.17 and increased to 0.18 after adjusting for the effects of given covariates. Each 10% increase in dietary lutein + zeaxanthin was associated with a 1% increase in serum conditional on other terms in the model. Many factors that influence the level of serum lutein + zeaxanthin remain unknown.     

Acculturation in the United States is associated with lower serum carotenoid levels: Third National Health and Nutrition Examination Survey

This study examined the association of acculturation in the United States and serum carotenoid levels. The design was a cross-sectional, nationally representative survey of 16,539 participants, 17 years of age and older, from the Third National Health and Nutrition Examination Survey (NHANES III). The main outcome measures were serum levels of alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein/zeaxanthin, lycopene, and total carotenoids. Multivariate linear regression was used to model the association of serum carotenoids and country of birth, language of interview, and years in the United States. Adjustments were made for age, sex, years of education, race/ethnicity, body mass index, alcohol use, physical activity, serum cotinine, serum cholesterol, and vitamin/mineral usage. Individuals born in the United States who speak English had the lowest levels of carotenoids, and individuals born in Mexico had the highest levels of carotenoids, with the exception of lycopene. Years of residence in the United States was associated with lower alpha-carotene (4.18 vs 1.51), beta-carotene (20.21 vs 14.87), beta-cryptoxanthin (12.51 vs 8.95), lutein/zeaxanthin (25.15 vs 18.03), and total carotenoids (88.79 vs 75.44). Years residence in the United States was positively associated with higher lycopene levels (26.69 vs 32.03). Acculturation in the United States was associated with lower fruit and vegetable intake, as measured by serum carotenoid levels.     

Total homocysteine and estrogen status indicators in the Third National Health and Nutrition Examination Survey

The possibility that estrogen status modulates total homocysteine concentration, a risk factor for vascular occlusion, was examined in a representative sample of the US population, the Third National Health and Nutrition Examination Survey (phase 2), 1991-1994. The geometric mean serum total homocysteine concentration was compared among population subgroups differing on inferred estrogen status, after adjusting for potential confounding by age, race-ethnicity, smoking, and the serum concentration of creatinine, folate, and vitamin B-12. Premenopausal women aged 17-54 years had a lower mean serum total homocysteine concentration (8.1 micromol/liter, 95% confidence interval (CI): 7.9, 8.2) than men in the same age range (8.9 micromol/liter, 95% CI: 8.6, 9.3). In the age range 17-44 years, pregnant women (6.0 micromol/liter, 95% CI: 5.4, 6.8), but not oral contraceptive users (7.9 micromol/liter, 95% CI: 7.6, 8.2), had a lower mean serum total homocysteine concentration than nonpregnant, non-oral-contraceptive-using women (8.1 micromol/liter, 95% CI: 7.9, 8.2). The mean serum total homocysteine concentration of estrogen-using women aged > or = 55 years (9.5 micromol/liter, 95% CI: 8.9, 10.1) was significantly decreased relative to nonestrogen users (10.7 micromol/liter, 95% CI: 10.3, 11.1) and men (10.4 micromol/liter, 95% CI: 9.8, 11.0) in the same age range. These findings suggest that higher estrogen status is associated with a decreased mean serum total homocysteine concentration, independent of nutritional status and muscle mass, and that estrogen may explain the previously reported male-female difference in total homocysteine concentration.     

Vitamin C deficiency and depletion in the United States: the Third National Health and Nutrition Examination Survey, 1988 to 1994

OBJECTIVES: We sought to determine prevalence rates of vitamin C deficiency and depletion in the United States. METHODS: We used data from the Third National Health and Nutrition Examination Survey to assess intake of dietary, supplemental, and serum vitamin C. RESULTS: Mean intakes and serum levels of vitamin C were normal; however, vitamin C deficiency and depletion were common (occurring among 5%-17% and 13%-23% of respondents, respectively). Smokers, those who did not use supplements, and non-Hispanic Black males had elevated risks of vitamin C deficiency, while Mexican Americans had lower risks. CONCLUSIONS: Health professionals should recommend consumption of vegetables and fruits rich in vitamin C and should recommend supplementation for individuals at risk of vitamin C deficiency.     

Salad and raw vegetable consumption and nutritional status in the adult US population: results from the Third National Health and Nutrition Examination Survey

OBJECTIVE: To examine the relationship between reported salad consumption and serum nutrient levels as well as dietary adequacy, as defined by nutrient intakes, in relation to the National Academy of Science Food and Nutrition Board Guidelines, in pre- and postmenopausal women and in men of comparable ages. DESIGN: Analyses of 24-hour recalls were conducted to determine dietary intake using the Third National Health and Nutrition Examination Survey data. Salad consumption was assessed based on intakes of salad, raw vegetables, and salad dressing. SUBJECTS: Nine thousand four hundred-six women and 8,282 men aged 18 to 45 years and older than 55 years were examined between 1988 and 1994. STATISTICAL ANALYSES: Regressions were used to model associations between salad and raw vegetable consumption and selected serum nutrient outcomes. Usual nutrient intake distributions were estimated using the Iowa State University method for adjustment of the distribution. The Estimated Average Requirement method was used to determine the proportion of subjects with inadequate intake for each nutrient. RESULTS: The consumption of salads, raw vegetables, and salad dressing was positively associated with above-median serum micronutrient levels of folic acid, vitamins C and E, lycopene, and alpha- and beta-carotene. Each serving of salad consumed was associated with a 165% higher likelihood to meet the recommended Dietary Allowance for vitamin C in women and 119% greater likelihood in men. CONCLUSIONS: Salad consumers tended to have more favorable intakes of vitamins C and E, folic acid, and carotenoids, after adjustment for other differences. The significant and consistently higher serum values of these vitamins among salad consumers suggest that they are being well absorbed from salad. Salad, salad dressing, and raw vegetable consumption can be an effective strategy for enhancing nutritional adequacy and increasing vegetable consumption in the population at large.     

Serum retinol distributions in residents of the United States: third National Health and Nutrition Examination Survey, 1988-1994

BACKGROUND: Inadequate vitamin A status has been a potential nutritional problem for some segments of the US population, particularly children and the poor. OBJECTIVE: We evaluated serum retinol concentration by using population-representative data from 16058 participants aged 4 to >/=90 y in the third National Health and Nutrition Examination Survey, 1988-1994. DESIGN: We used multivariate regression to examine the simultaneous associations of sociodemographic, biologic, and behavioral factors with serum retinol concentration. RESULTS: In children, serum retinol concentrations were greater with greater age, body mass index, serum lipids, and the use of supplements containing vitamin A. In adults, male sex, serum lipids, alcohol consumption, and age were positively associated with serum retinol concentration in most racial/ethnic strata. Household income was not associated with serum retinol concentration in children; associations were inconsistent in adults. The prevalence of serum retinol <0.70 micromol/L was very low in all strata; the prevalence of serum retinol <1.05 micromol/L was 16.7-33.9% in children aged 4-8 y and 3.6-14.2% in children aged 9-13 y, depending on sex and racial/ethnic group. The prevalence of serum retinol<1.05 micromol/L was higher in non-Hispanic black and Mexican American children than in non-Hispanic white children; these differences remained significant (P < 0.0001) after covariates were controlled for. Among adults, nonwhite women were significantly (P < 0.0001) more likely than white women to have serum retinol <1.05 micromol/L after covariates were controlled for. CONCLUSIONS: Clinically low serum retinol concentration is uncommon in US residents aged > or = 4 y, although racial/ethnic and socioeconomic differences in serum retinol concentration still exist.     

Prevalence in the United States of selected candidate gene variants: Third National Health and Nutrition Examination Survey, 1991-1994

Population-based allele frequencies and genotype prevalence are important for measuring the contribution of genetic variation to human disease susceptibility, progression, and outcomes. Population-based prevalence estimates also provide the basis for epidemiologic studies of gene-disease associations, for estimating population attributable risk, and for informing health policy and clinical and public health practice. However, such prevalence estimates for genotypes important to public health remain undetermined for the major racial and ethnic groups in the US population. DNA was collected from 7,159 participants aged 12 years or older in Phase 2 (1991-1994) of the Third National Health and Nutrition Examination Survey (NHANES III). Certain age and minority groups were oversampled in this weighted, population-based US survey. Estimates of allele frequency and genotype prevalence for 90 variants in 50 genes chosen for their potential public health significance were calculated by age, sex, and race/ethnicity among non-Hispanic whites, non-Hispanic blacks, and Mexican Americans. These nationally representative data on allele frequency and genotype prevalence provide a valuable resource for future epidemiologic studies in public health in the United States.     

Relations of serum ascorbic acid and alpha-tocopherol to diabetic retinopathy in the Third National Health and Nutrition Examination Survey

The protective relation of ascorbic acid and alpha-tocopherol to the development of diabetic retinopathy has not been thoroughly evaluated in epidemiologic studies. The association of prevalent diabetic retinopathy with serum ascorbic acid and alpha-tocopherol was studied among participants with type 2 diabetes (>or=40 years) (n = 998) in the Third National Health and Nutrition Examination Survey (1988-1994); 20% of the sample (n = 199) had prevalent retinopathy. The overall odds ratio for retinopathy among participants in quartile 4 compared with quartile 1 for serum ascorbic acid was 1.3 (95% confidence interval: 0.8, 2.3), with a p for trend = 0.60 after adjustment for the confounders of smoking, race, waist/hip ratio, hypertension, and duration of diabetes. The overall odds ratio for retinopathy among participants in quartile 4 compared with quartile 1 for serum alpha-tocopherol was 2.7 (95% confidence interval: 1.6, 4.6), with a p for trend = 0.14 after adjustment for confounders. After removal of supplement users of vitamin C (n = 307) or vitamin E (n = 298), the odds ratio changed direction or was attenuated: adjusted odds ratios for retinopathy among participants in quartile 4 compared with quartile 1 for serum ascorbic acid and alpha-tocopherol = 0.7 (95% confidence interval: 0.3, 1.4) and 1.6 (95% confidence interval: 0.9, 2.9), respectively. In summary, no significant associations were observed between serum levels of major dietary antioxidants and retinopathy. Recent use of supplements for treatment of complications of diabetes may explain the direct associations.     

Population determinants of serum lycopene concentrations in the United States: data from the Third National Health and Nutrition Examination Survey, 1988-1994

Serum lycopene is inversely related to the risk for cancer and cardiovascular diseases. We used data from the Third National Health and Nutrition Examination Survey, 1988-1994, to investigate the relation between serum lycopene concentrations and sex, age, geographical location, race-ethnicity, education, alcohol, smoking, BMI, blood pressure, serum total cholesterol and triacylglycerol, and intakes of fat, tomatoes and tomato-based products in 3413 individuals aged 17-90 y. Multivariate adjusted mean lycopene concentrations were 48.3% lower in individuals > or =70 y old than in those 17 to <30 y old (P < 0.0001), 7.6% lower in women than in men (P = 0.0045), 15.1% lower in people living in the South than those in the West (P < 0.0001), 10.3 and 61.0% lower in the 1st quartile than in the 4th quartile for dietary fat intake (P = 0.0173) and serum cholesterol (P < 0.0001), respectively, 11.1% lower in tomato noneaters than those who ate tomatoes > or =31 times/mo (P = 0.0085), 13.5% lower in pizza noneaters than those who ate pizza > or =16 times/mo (P = 0.0016), and 20.6% lower in pasta noneaters than those who ate pasta (with tomato sauce) > or =16 times/mo (P < 0.0001). Race-ethnicity, alcohol, BMI, blood pressure, and consumption of non-tomato vegetables, and fruits and juices had no association with serum lycopene concentrations. Sex, age, geographical region, socioeconomic status, serum total cholesterol, smoking, and intakes of fat, tomatoes, pizza, and pasta were significant determinants of serum lycopene concentrations in the United States.     

Serum vitamins, carotenoids, and angina pectoris: findings from the National Health and Nutrition Examination Survey III

PURPOSE: Whether various vitamins and carotenoids can protect against ischemic heart disease remains an unsettled question. METHODS: We performed a cross-sectional analysis of data from National Health and Nutrition Examination Survey III (1988-1994) and examined the associations between serum vitamins A, C, E, and B12, serum folate, red blood cell folate, serum carotenoids, and angina pectoris in a representative population-based sample of 11,327 men and women aged 35->90 years. RESULTS: After adjusting for age, sex, race or ethnicity, education, smoking status, systolic blood pressure, serum cholesterol, high-density lipoprotein cholesterol, history of diabetes mellitus, body mass index, and physical activity with multiple logistic regression analysis, no significant associations were present for any of the serum vitamin concentrations and angina pectoris. Significant linear trends were observed for serum concentrations of alpha-carotene (p < 0.001), beta-carotene (p = 0.026), and beta-cryptoxanthin (p = 0.003). Compared with participants with carotenoid concentrations in the lowest quartile, participants with concentrations in the highest quartile had odds ratios for angina pectoris of 0.45 (95% confidence interval (CI) 0.31-0.65), 0.57 (95% CI 0.38-0.86), and 0.57 (95% CI 0.38-0.84) for alpha-carotene, beta-carotene, and beta-cryptoxanthin, respectively. CONCLUSIONS: These results provide little support for a cross-sectional association between angina pectoris and serum and red blood cell folate concentrations or concentrations of vitamins A, C, E, and B12. Several serum carotenoid concentrations were associated with a reduced risk for angina pectoris, however.     

Association between lung function and mental health problems among adults in the United States: findings from the First National Health and Nutrition Examination Survey

The objective of this study was to determine the association between lung function and mental health problems among adults in the United States. Data were drawn from the First National Health and Nutrition Examination Survey (1971-1975), with available information on a representative sample of US adults aged 25-74 years. Lung function was assessed by spirometry, and provisional diagnoses of restrictive and obstructive airway disease were assigned based on percentage of expected forced expiratory volume. Mental health problems were assessed with the General Well-Being scales. Restrictive lung function and obstructive lung function, compared with normal lung function, were each associated with a significantly increased likelihood of mental health problems. After adjustment for differences in demographic characteristics, obstructive lung function was associated with significantly lower overall well-being (p = 0.025), and restrictive lung function was associated with significantly lower overall well-being (p < 0.001), general health (p < 0.0001), vitality (p < 0.0001), and self-control (p = 0.001) and with higher depression (p = 0.002) subscale scores compared with no lung function problems. Consistent with previous findings from clinical and community-based studies, these results extend available data by providing evidence of a link between objectively measured lung function and self-reported mental health problems in a representative sample of community adults. Future studies are needed to determine the mechanisms of these associations.     

The associations between blood lipids and the Food Guide Pyramid: findings from the Third National Health and Nutrition Examination Survey

BACKGROUND: Dietary recommendations are based on nutrients, foods, and food groups, but the relationship between the Food Guide Pyramid (FGP) food groups and serum lipids has not been studied. METHODS: NHANES III data were obtained for US adults who met the following criteria: aged 20-59 years, reliable participant, and typical 24-h recall. We examined whether serum lipids (serum total cholesterol (STC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triacylglycerol) were related to FGP food group intake (dairy, fruit, grain, meat, and vegetable). RESULTS: A sample of 9111 participants qualified for this analysis. Fruit intakes were inversely related to STC, HDL-C, and LDL-C (P = 0.012, P = 0.001, and P = 0.014, respectively) and directly related to triacylglycerol levels (P = 0.003). Grain intake was inversely associated with both STC and HDL-C (P = 0.020 and P = 0.000). Dairy and meat intakes were directly related to LDL-C (P = 0.026 and P = 0.020). CONCLUSIONS: Food groups are related to serum lipids. Universal definitions for food groups are needed in research and nutrition education. Studying the relationships between food groups and serum lipids is important for future dietary recommendations related to serum lipids.     

Distributions and Trends of Serum Lipid Levels among United States Children and Adolescents Ages 4–19 Years: Data from the Third National Health and Nutrition Examination Survey

Background.Atherosclerosis begins in childhood and progresses into adulthood. The reduction of cardiovascular risk factors, such as elevated serum total cholesterol and low-density lipoprotein cholesterol (LDL-C) levels, in childhood may reduce cardiovascular morbidity and mortality in adulthood. Lipid distributions among children and adolescents were examined using the most recent nationally representative data.Methods.Data from 7,499 examinees in NHANES III (1988–1994) were used to estimate mean and percentile distributions of serum total cholesterol, LDL-C, high-density lipoprotein cholesterol (HDL-C), and triglycerides in children and adolescents aged 4 to 19 years. The estimates were analyzed by age, sex, and race/ethnic groups. Trends in mean total cholesterol were examined for 12- to 17-year-olds using data from NHES III (1966–1970), NHANES I (1971–1974), and NHANES III (1988–1994).Results.For children and adolescents 4 to 19 years of age, the 95th percentile for serum total cholesterol was 216 mg/dL and the 75th percentile was 181 mg/dL. Mean age-specific total cholesterol levels peaked at 171 mg/dL at 9–11 years of age and fell thereafter. Females had significantly higher mean total cholesterol and LDL-C levels than did males (P< 0.005). Non-Hispanic black children and adolescents had significantly higher mean total cholesterol, LDL-C, and HDL-C levels compared to non-Hispanic white and Mexican American children and adolescents. The mean total cholesterol level among 12- to 17-year-olds decreased by 7 mg/dL from 1966–1970 to 1988–1994 and is consistent with, but less than, observed trends in adults. Black females have experienced the smallest decline between surveys.Conclusions.The findings provide a picture of the lipid distribution among U.S. children and adolescents and indicate that, like adults, adolescents have experienced a fall in total cholesterol levels. Total cholesterol levels in U.S. adolescents declined from the late 1960s to the early 1990s by an average of 7 mg/dL. This information is useful for planning programs targeting the prevention of cardiovascular disease beginning with the development of heathy lifestyles in childhood.     

Lipids and pulmonary function in the Third National Health and Nutrition Examination Survey

Studies considering the association between total cholesterol and noncardiovascular mortality, particularly from respiratory disease, yield inconclusive findings. To explore this question, the relation of lipids to pulmonary function, specifically forced expiratory volume in 1 second (FEV(1)), was investigated in the Third National Health and Nutrition Examination Survey. Conducted in the United States in 1988-1994 among adults aged > or =17 years, this survey measured serum lipids, FEV(1), and confounding factors including smoking and antioxidants. Multiple linear regression analysis explored the relation of FEV(1)/height(2) to low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol, and their respective apolipoproteins (apo) B and A-I. A standard deviation increase in HDL cholesterol or apo A-I was associated with an FEV(1) increase of 43 ml (95% confidence interval (CI): 30, 56) or 29 ml (95% CI: 11, 47), respectively, for an average-height adult. A standard deviation increase in LDL cholesterol or apo B was associated with an FEV(1) decrease of -24 ml (95% CI: -43, -5) or -53 ml (95% CI: -74, -32), respectively, adjusted for serum antioxidant status. The lipid subfractions were differentially associated with FEV(1) consistent with the possibility that LDL cholesterol contributes to endogenous oxidative burden while HDL cholesterol attenuates inflammatory tissue damage. Whether these associations are causal remains to be determined.     

Racial differences in serum selenium concentration: analysis of US population data from the Third National Health and Nutrition Examination Survey

Lower intake of the essential trace element selenium may be a risk factor for prostate cancer and other cancers. In the United States, many racial disparities in cancer incidence, such as the 61% higher incidence of prostate cancer among Blacks relative to Whites, remain unexplained. Using data from a large, nationally representative survey, the authors explored Black/White differences in serum selenium concentration. Mean serum selenium concentrations, both crude and adjusted for known predictors of serum selenium, were determined for 10,779 Black and White males and females aged >or=12 years who participated in the Third National Health and Nutrition Examination Survey (1988-1994). Crude mean serum selenium concentrations were 126.35 ng/ml for Whites and 118.76 ng/ml (approximately 6% lower) for Blacks. Adjustment for known serum selenium predictors, including a proxy for residence at the county level, reduced the racial disparity, although concentrations remained approximately 3% lower in Blacks than in Whites of both sexes (p<0.0001). The observation that Blacks had lower unadjusted and adjusted serum selenium concentrations relative to Whites is intriguing, given the racial disparity in incidence of prostate cancer and other cancers.     

Gender differences in risk factors for attempted suicide among young adults: findings from the Third National Health and Nutrition Examination Survey

PURPOSE: To identify the significant factors associated with attempted suicide among men and women, and determine whether socioeconomic status (SES) and social support indictors, health risk factors, and lifetime history of medical and psychiatric illnesses can explain gender differences in attempted suicide. METHODS: We used data from 3357 men and 4004 women aged 17 to 39 years, who completed a mental disorder diagnostic interview as a part of the Third National Health and Nutrition Examination Survey, 1988-1994. Adjusted odds ratios (ORs) were calculated for the association between risk factors and attempted suicide. RESULTS: The prevalence of lifetime attempted suicides was 7.58% (SE, 0.66) in women and 3.69% (SE, 0.49) in men. In men, low income and smoking were associated with attempted suicide, while attempted suicide in women was associated with poor self-evaluated health, low educational attainment, and drug use. A history of medical and psychiatric illnesses was associated with attempted suicide in both genders, for cancer/pulmonary disease, OR=2.89 (95% CI, 1.25-6.67) in men and 1.94 (1.09-3.45) in women; for major depressive disorder, OR=9.86 (5.08-19.14) in men and 5.00 (3.19-7.83) in women. The significant gender difference of attempted suicide prevalence remained after being adjusted for risk factors selected. CONCLUSION: There were significant gender differences in the risk factors for attempted suicide among young adults, and the gender difference in the prevalence of lifetime attempted suicides could not be explained by differential exposure to risk factors selected.