The epidemiology of recent involuntary weight loss in the United States population.

BACKGROUND: Although recent involuntary weight loss (RIWL) has been associated with mortality, no national studies described the prevalence among the general population, characteristics and long-term outcomes of people with RIWL. METHODS: The authors analyzed data from the NHANES II Mortality Study of 5838 individuals 50-74.9 years old who between 1976-1980 underwent a physical examination that included height and weight measurements, biochemical tests and responded to questions about involuntary weight loss within the past six months. Vital status was determined through 1992. Logistic regression was used to examine characteristics associated with RIWL and Cox proportional hazard modeling was used to measure associations between RIWL and mortality. RESULTS: 13.3% of the population reported RIWL with 6.9% reporting > or = 5% RIWL. Obese individuals were at significantly higher risk of RIWL of > or = 5% compared to those with BMI 19-24.9 (OR=1.57. 95% CI: 1.13, 2.18). Other significant risk factors for RIWL included; poor self-reported health, cancer, high white blood cell count, low albumin and low hemoglobin levels, age and current smoking status. RIWL of > or = 5% was significantly associated with mortality (RR=1.24, 95% CI: 1.01, 1.53). CONCLUSION: In summary, RIWL is fairly common among community-dwelling older adults, occurs disproportionately among obese individuals, is associated with characteristics of poor health and independently associated with mortality. These results indicate that RIWL needs to be considered an adverse health indicator even among obese individuals and despite the absence of several clinical indicators of disease.

Estrogen replacement therapy and incidence of self-reported physician-diagnosed arthritis.

BACKGROUND: This longitudinal study examined the association between use of estrogen replacement therapy and incidence of self-reported, physician-diagnosed arthritis. METHODS: Data of 2,416 postmenopausal women who participated in the National Health and Nutrition Examination Survey Epidemiological Follow-Up Study were used in this study. Women, free of self-reported arthritis at entry into study and for 3 years thereafter, were questioned about use of estrogen and physician-diagnosed arthritis at each of the follow-up waves of study. Proportional hazard regression models were used for the analysis. RESULTS: Use of ERT was found to be associated with higher risk of incident arthritis, after adjusting for potential confounders (RR = 1.61, CI 1.37-1.89). Whenever use of ERT was replaced by duration of use in the regression model, ERT users for a year or less significantly increased their risk of incident arthritis (RR = 1.37, CI 1.07-1.74). The risk increased by 30 and 96% with hormone use for 1 to 4 and 4 to 10 years, respectively, and by 104% with hormone use for 10 or more years. CONCLUSION: Results suggest that users of ERT were at higher risk of developing arthritis and the longer the use of the hormone, the higher the risk.

Body mass index, weight change, and incidence of self-reported physician-diagnosed arthritis among women.

OBJECTIVES: This study examined the relationship between body mass index (BMI), weight change, and arthritis in women. METHODS: Data were taken from the 1982-1984 National Health and Nutrition Examination Survey Epidemiologic Follow-Up Study of 3617 women, aged 25 to 74 years. RESULTS: Women with a BMI greater than 32 at initial interview were at significantly higher risk of developing arthritis than women with a BMI of 19 to 21.9. Compared with stable-weight women with a BMI of less than 25, women who were obese at initial interview (BMI > 29) and who subsequently maintained their weight or gained more than 10% of their body weight were at significantly higher risk of developing arthritis. CONCLUSIONS: Attaining and maintaining a healthy weight may reduce the risk of developing arthritis.

Income inequality and mortality in metropolitan areas of the United States.

OBJECTIVES: This study examined associations between income inequality and mortality in 282 US metropolitan areas. METHODS: Income inequality measures were calculated from the 1990 US Census. Mortality was calculated from National Center for Health Statistics data and modeled with weighted linear regressions of the log age-adjusted rate. RESULTS: Excess mortality between metropolitan areas with high and low income inequality ranged from 64.7 to 95.8 deaths per 100,000 depending on the inequality measure. In age-specific analyses, income inequality was most evident for infant mortality and for mortality between ages 15 and 64. CONCLUSIONS: Higher income inequality is associated with increased mortality at all per capita income levels. Areas with high income inequality and low average income had excess mortality of 139.8 deaths per 100,000 compared with areas with low inequality and high income. The magnitude of this mortality difference is comparable to the combined loss of life from lung cancer, diabetes, motor vehicle crashes, human immunodeficiency virus (HIV) infection, suicide, and homicide in 1995. Given the mortality burden associated with income inequality, public and private sector initiatives to reduce economic inequalities should be a high priority.

Are geographic regions with high income inequality associated with risk of abdominal weight gain?

Geographic regions characterized by income inequality are associated with adverse mortality statistics, but the pathophysiologic mechanisms that mediate this ecologic relationship have not been elucidated. This study used a United States mail survey of 34158 male and 42741 female healthy-adult volunteers to test the association between residence in geographic regions with relative income inequality and the likelihood of weight gain at the waist. Respondents came from 21 states that were characterized by the household income inequality (HII) index, a measure reflecting the proportion of total income received by the more well off 50% of households in the state. The main outcome measure was self-reported weight gain mainly at the waist as opposed to weight gain at other anatomic sites. After controlling for age, other individual-level factors, and each state's median household income, men's likelihood of weight gain at the waist was positively associated (p = 0.0008) with the HII index. Men from states with a high HII (households above the median receive 81.6% to 82.6% of the income) described weight gain at the waist more often than men from states with a low HII (households above the median receive 77.0% to 78.5% of the income) (odds ratio = 1.12, 95% confidence interval 1.03 to 1.22). Women's results showed a non-significant trend in the same direction. An association between ecologically defined socio-environmental stress and abdominal obesity may help to clarify the pathophysiologic pathways leading to several major chronic diseases.

The effect of age on the association between body-mass index and mortality.

BACKGROUND: The effect of age on optimal body weight is controversial, and few studies have had adequate numbers of subjects to analyze mortality as a function of body-mass index across age groups. METHODS: We studied mortality over 12 years among white men and women who participated in the American Cancer Society's Cancer Prevention Study I (from 1960 through 1972). The 62,116 men and 262,019 women included in this analysis had never smoked cigarettes, had no history of heart disease, stroke, or cancer (other than skin cancer) at base line in 1959-1960, and had no history of recent unintentional weight loss. The date and cause of death for subjects who died were determined from death certificates. The associations between body-mass index (defined as the weight in kilograms divided by the square of the height in meters) and mortality were examined for six age groups in analyses in which we adjusted for age, educational level, physical activity, and alcohol consumption. RESULTS: Greater body-mass index was associated with higher mortality from all causes and from cardiovascular disease in men and women up to 75 years of age. However, the relative risk associated with greater body-mass index declined with age. For example, for mortality from cardiovascular disease, the relative risk associated with an increment of 1 in the body-mass index was 1.10 (95 percent confidence interval, 1.04 to 1.16) for 30-to-44-year-old men and 1.03 (95 percent confidence interval, 1.02 to 1.05) for 65-to-74-year-old men. For women, the corresponding relative risk estimates were 1.08 (95 percent confidence interval, 1.05 to 1.11) and 1.02 (95 percent confidence interval, 1.02 to 1.03). CONCLUSIONS: Excess body weight increases the risk of death from any cause and from cardiovascular disease in adults between 30 and 74 years of age. The relative risk associated with greater body weight is higher among younger subjects.

Validity of self-reported hypertension in the National Health and Nutrition Examination Survey III, 1988-1991.

BACKGROUND: The National Health and Nutrition Examination Survey (NHANES) is the main data source for hypertension surveillance. However, because of a gap of almost 10 years between each NHANES, self-reported data from annual surveys need to be examined as an alternative data source. This study analyzes the validity of self-reported hypertension in a national sample of non-Hispanic whites, non-Hispanic blacks, and Mexican-Americans. METHODS: Sensitivity, specificity, and predictive values positive (PVP) and negative (PVN) of self-reported hypertension were calculated against two definitions of hypertension: the definition recommended by the Third Joint National Committee on Hypertension, JNC III (blood pressure > or = 140/90 and/or taking antihypertension medication) and a broader definition including control with lifestyle modifications. Data used come from the NHANES III, 1988-1991. RESULTS: Overall test characteristics using the JNC III definition are sensitivity 71%, specificity 90%, PVP 72%, and PVN 89%. Test characteristics were consistently higher for the broad than for the JNC III definition. Validity of self-reported hypertension is higher among women than among men and among persons with a medical visit during the past year than among those with no visits: validity was lowest among Mexican-American men. Due to the similarity between sensitivity and PVP, the prevalence of self-reported hypertension is nearly equal to the prevalence of JNC III-defined hypertension. CONCLUSIONS: Self-reported hypertension may be used for surveillance of hypertension trends, in the absence of measured blood pressure, among non-Hispanic whites and non-Hispanic black women and persons with a medical visit in the past year. Validation should be repeated with each NHANES.

Explaining the relation between education and postmenopausal breast cancer.

The authors examined the relation between socioeconomic status, as defined by education level, and postmenopausal breast cancer incidence using data from the National Health and Nutrition Examination Survey I Epidemiologic Followup Study. Female participants in the study were followed from 1971-1974 to 1992-1993. Cox proportional hazards modeling was used to determine the relation between breast cancer incidence and education level. There was a direct dose-response association between education level and postmenopausal breast cancer risk. Several breast cancer risk factors, including height and reproductive-related risks such as nulliparity, were found to mediate this relation. Adjustment for these factors reduced, but did not eliminate, the positive relation between education level and risk of postmenopausal breast cancer; however, the association was no longer statistically significant. The association between higher education and increased risk of breast cancer appears to be largely explained by differences in the known risk factors for breast cancer.

Inequality in income and mortality in the United States: analysis of mortality and potential pathways.

OBJECTIVE: To examine the relation between health outcomes and the equality with which income is distributed in the United States. DESIGN: The degree of income inequality, defined as the percentage of total household income received by the less well off 50% of households, and changes in income inequality were calculated for the 50 states in 1980 and 1990. These measures were then examined in relation to all cause mortality adjusted for age for each state, age specific deaths, changes in mortalities, and other health outcomes and potential pathways for 1980, 1990, and 1989-91. MAIN OUTCOME MEASURE: Age adjusted mortality from all causes. RESULTS: There was a significant correlation (r = -0.62 [corrected], P < 0.001) between the percentage of total household income received by the less well off 50% in each state and all cause mortality, unaffected by adjustment for state median incomes. Income inequality was also significantly associated with age specific mortalities and rates of low birth weight, homicide, violent crime, work disability, expenditures on medical care and police protection, smoking, and sedentary activity. Rates of unemployment, imprisonment, recipients of income assistance and food stamps, lack of medical insurance, and educational outcomes were also worse as income inequality increased. Income inequality was also associated with mortality trends, and there was a suggestion of an impact of inequality trends on mortality trends. CONCLUSION: Variations between states in the inequality of the distribution of income are significantly associated with variations between states in a large number of health outcomes and social indicators and with mortality trends. These differences parallel relative investments in human and social capital. Economic policies that influence income and wealth inequality may have an important impact on the health of countries.

Associations between measures of socioeconomic status and maternal health behavior.

Lower socioeconomic status (SES) is consistently associated with adverse pregnancy outcomes. One mechanism that may account for this association is that maternal health behaviors vary with SES. To examine this possibility, we addressed how women may be differently categorized by diverse measures of SES and the effect that choice of measure has on the relationship between SES and maternal health behaviors. We used population-based data for Caucasian women (n = 10,055) from Alaska, Maine, Oklahoma, and West Virginia who delivered a live infant in 1990-1991 and participated in the Pregnancy Risk Assessment Monitoring System. Five SES measures were evaluated: education; poverty status; Medicaid payment for delivery; Women, Infants, and Children (WIC) enrollment during pregnancy; and residential crowding. Three maternal health behaviors (smoking, delayed/no prenatal care, unintended pregnancy) were examined to assess the variation among the associations between SES measures and behaviors. Item response rates were high for all SES measures (range: 88.9%-100.0%), and there was low correlation between measures. Most of the SES measures were related to maternal health behaviors. However, the strength of association varied between each measure and behavior and was weaker for women who were younger than 20 years old or not married. In view of the multifaceted nature of SES, several measures may be needed to appropriately assess the relationship between SES and maternal health behaviors.

The influence of smoking cessation on the prevalence of overweight in the United States.

BACKGROUND: The proportion of U.S. adults 35 to 74 years of age who were overweight increased by 9.6 percent for men and 8.0 percent for women between 1978 and 1990. Since the prevalence of smoking declined over the same period, smoking cessation has been suggested as a factor contributing to the increasing prevalence of overweight. METHODS: To estimate the influence of smoking cessation on the increase in the prevalence of overweight, we analyzed data on current and past weight and smoking status for a national sample of 5247 adults 35 years of age or older who participated in the third National Health and Nutrition Examination Survey, conducted from 1988 through 1991. The results were adjusted for age, sociodemographic characteristics, level of physical activity, alcohol consumption, and (for women) parity. RESULTS: The weight gain over a 10-year period that was associated with the cessation of smoking (i.e., the gain among smokers who quit that was in excess of the gain among continuing smokers) was 4.4 kg for men and 5.0 kg for women. Smokers who had quit within the past 10 years were significantly more likely than respondents who had never smoked to become overweight (odds ratios, 2.4 for men and 2.0 for women). For men, about a quarter (2.3 of 9.6 percentage points) and for women, about a sixth (1.3 of 8.0 percentage points) of the increase in the prevalence of overweight could be attributed to smoking cessation within the past 10 years. CONCLUSIONS: Although its health benefits are undeniable, smoking cessation may nevertheless be associated with a small increase in the prevalence of overweight.

Effects of question order on estimates of the prevalence of attempted weight loss.

Although numerous surveys have been conducted to estimate the prevalence of attempted weight loss, little information is available on the possible effects of question order on the prevalence estimates. The authors examined data collected from 231,852 respondents to surveys conducted in the District of Columbia and 20 states that participated in the Behavioral Risk Factor Surveillance System between 1985 and 1992. In surveys conducted from 1985 to 1988, respondents (n = 117,827) were first asked their body weight and then were asked if they were trying to lose weight; 48% of the women and 29% of the men reported that they were trying to lose weight. In 1989, 1991, and 1992 (no questions about weight control were asked in 1990), the order of the questions was reversed so that respondents (n = 114,025) were asked whether they were trying to lose weight before they were asked to report their weight; 41% of the women and 26% of the men reported that they were trying to lose weight. The authors conclude that survey respondents, especially women, may be more likely to report that they are trying to lose weight when questions about weight control practices immediately follow questions on current weight. This apparent effect of question order points to the need for caution in comparing prevalence estimates across surveys in which the questions are not asked in a similar order, even when the questions are worded identically.

Effect of smoking on serum nutrient concentrations in African-American women.

The relationship between current cigarette smoking and serum concentrations of vitamins C, E, and A, and of five carotenoids in human serum were examined in 91 low-income, African-American women. General linear models were used to adjust geometric mean serum concentrations of micronutrients for age, dietary and supplement intakes, total energy intake, alcohol intake, medication use, body mass index, and serum concentrations of cholesterol and triglycerides. Among smokers, serum concentrations of alpha-carotene, beta-carotene, cryptoxanthin, and lycopene averaged only 71-79% of the concentrations among nonsmokers. Mean serum concentrations of vitamins C and E and lutein/zeaxanthin were only slightly lower among smokers relative to nonsmokers, and current smokers had higher serum concentrations of vitamin A. Among current smokers, mean serum concentrations of all five carotenoids decreased with an increase in the amount smoked. The negative effect of smoking on serum concentrations of antioxidant carotenoids may pose a serious health risk in low-income populations already at higher risk for many chronic diseases.

The association between weight loss and increased longevity. A review of the evidence.

Six published observational epidemiologic studies have reported evidence of reduced mortality rates in persons who have lost weight. In two studies, the reported protective effects of weight loss on mortality could not be justified by the data. In two other studies, weight loss was associated with both increased and decreased longevity in different subgroups. Only one study provided information on whether the weight loss was voluntary, but this study found similar effects of weight loss regardless of volition. These studies provided only limited information on the magnitude of weight loss associated with changes in longevity and no information on the types of methods used to achieve weight loss. Because of difficulties in studying long-term health outcomes related to obesity treatment, randomized, controlled trials are unlikely to provide a practical study design for this issue. Properly designed observational studies will probably provide the most useful information on the effects of voluntary weight loss on longevity.

Weight loss and subsequent death in a cohort of U.S. adults.

OBJECTIVE: Because we previously found that weight loss was associated with increased risk for death in all but very overweight men in a cohort of U.S. adults, we undertook a new analysis to determine whether inadequate control for preexisting illness or cigarette smoking contributed to this association. DESIGN: Cohort study. SETTING: The first National Health and Nutrition Examination Survey (NHANES I, 1971 to 1975) collected information on maximum lifetime weight and measured current weight on a probability sample of U.S. adults. The NHANES I Epidemiologic Follow-up Study determined the vital status of participants through 1987. PARTICIPANTS: Men (n = 2453) and women (n = 2739) who were 45 to 74 years old at the time of the NHANES I examination. RESULTS: The effect of excluding persons who died within the first 5 and first 8 years after baseline was examined to limit the influence of weight loss due to preexisting illness. For women, extension of the exclusionary period weakened the association between weight loss and increased risk for death from noncardiovascular disease. However, excluding death for as much as 8 years after baseline did not affect the strong association between weight loss and increased risk for death from cardiovascular disease among men and women with maximum body mass indexes between 26 and 29 (relative risks of up to 2.1 and 3.6 for men and women, respectively, after excluding deaths in the first 8 years). Results were not substantially altered by limiting the analysis to persons who never smoked. CONCLUSIONS: Preexisting illness may influence the association between weight loss and death principally through deaths from noncardiovascular disease. For some persons, weight loss is associated with an increased risk for death, even after excluding deaths occurring in the first 8 years.

Weight loss and mortality in a national cohort of adults, 1971-1987.

Although obesity is a risk factor for mortality, evidence that weight loss improves survival is limited. The relation between self-reported previous maximum weight, weight loss, and subsequent mortality was examined in 2,140 men and 2,550 women aged 45-74 years who participated in the First National Health and Nutrition Examination Survey (1971-1975) and survived the next 5 years. Vital status was determined through 1987. Among men and women whose maximum body mass index (weight (kg)/height (m)2) was between 26 and 29, risk of death increased with increasing weight loss, after adjustment for age, race, smoking, parity, preexisting illnesses, and maximum body mass index. Subjects who lost 15% or more of their maximum weight had over twice the mortality risk of those who lost less than 5%. At maximum body mass indices of 29 or higher, mortality risk increased with the amount of weight lost in women, but weight loss of 5% to < 15% appeared to lessen mortality risk in men. Generalization from these results is limited by the older age range of the sample and the inability to adequately distinguish voluntary from involuntary weight loss in this study. However, these findings suggest that prevention of severe overweight may be more generally effective than weight loss in reducing obesity-related mortality in the US population.

The quality of life in the year before death.

OBJECTIVES: Most Americans wish to live a long healthy life, but fear disease and dependency in their last years. Until recently, little has been known about the prevalence of opposite extremes of health in old age, particularly in the period leading up to death. METHODS: We used results from the 1986 National Mortality Follow-back Survey to estimate proportions of elderly decedents who were "fully functional" or "severely restricted" in the last year of life. Estimates were based on responses from proxies to questions regarding the decedent's functional status, mental awareness, and time spent in institutions. RESULTS: Approximately 14% of all decedents aged 65 years and older were defined as fully functional in the last year of life; 10% were defined as severely restricted. Proportions varied with the decedent's age and sex, the underlying cause of death, and the presence of other preexisting conditions. CONCLUSIONS: Results from this survey and future surveys can be used to learn more about "successful agers"--their medical histories, their life-styles, and whether their relative number is increasing or decreasing overtime.