Showing papers on "Body mass index published in 2002"

Prevalence and Trends in Obesity Among US Adults, 1999-2000

Abstract: ContextThe prevalence of obesity and overweight increased in the United States between 1978 and 1991. More recent reports have suggested continued increases but are based on self-reported data.ObjectiveTo examine trends and prevalences of overweight (body mass index [BMI] ≥25) and obesity (BMI ≥30), using measured height and weight data.Design, Setting, and ParticipantsSurvey of 4115 adult men and women conducted in 1999 and 2000 as part of the National Health and Nutrition Examination Survey (NHANES), a nationally representative sample of the US population.Main Outcome MeasureAge-adjusted prevalence of overweight, obesity, and extreme obesity compared with prior surveys, and sex-, age-, and race/ethnicity–specific estimates.ResultsThe age-adjusted prevalence of obesity was 30.5% in 1999-2000 compared with 22.9% in NHANES III (1988-1994; P<.001). The prevalence of overweight also increased during this period from 55.9% to 64.5% (P<.001). Extreme obesity (BMI ≥40) also increased significantly in the population, from 2.9% to 4.7% (P = .002). Although not all changes were statistically significant, increases occurred for both men and women in all age groups and for non-Hispanic whites, non-Hispanic blacks, and Mexican Americans. Racial/ethnic groups did not differ significantly in the prevalence of obesity or overweight for men. Among women, obesity and overweight prevalences were highest among non-Hispanic black women. More than half of non-Hispanic black women aged 40 years or older were obese and more than 80% were overweight.ConclusionsThe increases in the prevalences of obesity and overweight previously observed continued in 1999-2000. The potential health benefits from reduction in overweight and obesity are of considerable public health importance.

Prevalence and trends in overweight among us children and adolescents, 1999-2000

Abstract: ContextThe prevalence of overweight among children in the United States increased between 1976-1980 and 1988-1994, but estimates for the current decade are unknown.ObjectiveTo determine the prevalence of overweight in US children using the most recent national data with measured weights and heights and to examine trends in overweight prevalence.Design, Setting, and ParticipantsSurvey of 4722 children from birth through 19 years of age with weight and height measurements obtained in 1999-2000 as part of the National Health and Nutrition Examination Survey (NHANES), a cross-sectional, stratified, multistage probability sample of the US population.Main Outcome MeasurePrevalence of overweight among US children by sex, age group, and race/ethnicity. Overweight among those aged 2 through 19 years was defined as at or above the 95th percentile of the sex-specific body mass index (BMI) for age growth charts.ResultsThe prevalence of overweight was 15.5% among 12- through 19-year-olds, 15.3% among 6- through 11-year-olds, and 10.4% among 2- through 5-year-olds, compared with 10.5%, 11.3%, and 7.2%, respectively, in 1988-1994 (NHANES III). The prevalence of overweight among non-Hispanic black and Mexican-American adolescents increased more than 10 percentage points between 1988-1994 and 1999-2000.ConclusionThe prevalence of overweight among children in the United States is continuing to increase, especially among Mexican-American and non-Hispanic black adolescents.

Low relative skeletal muscle mass (sarcopenia) in older persons is associated with functional impairment and physical disability.

Abstract: OBJECTIVES: To establish the prevalence of sarcopenia in older Americans and to test the hypothesis that sarcope- nia is related to functional impairment and physical dis- ability in older persons. DESIGN: Cross-sectional survey. SETTING: Nationally representative cross-sectional sur- vey using data from the Third National Health and Nutri- tion Examination Survey (NHANES III). PARTICIPANTS: Fourteen thousand eight hundred eigh- teen adult NHANES III participants aged 18 and older. MEASUREMENTS: The presence of sarcopenia and the relationship between sarcopenia and functional impairment and disability were examined in 4,504 adults aged 60 and older. Skeletal muscle mass was estimated from bioimped- ance analysis measurements and expressed as skeletal mus- cle mass index (SMIskeletal muscle mass/body mass � 100). Subjects were considered to have a normal SMI if their SMI was greater than -one standard deviation above the sex-specific mean for young adults (aged 18-39). Class I sarcopenia was considered present in subjects whose SMI was within -one to -two standard deviations of young adult values, and class II sarcopenia was present in subjects whose SMI was below -two standard deviations of young adult values. RESULTS: The prevalence of class I and class II sarcope- nia increased from the third to sixth decades but remained relatively constant thereafter. The prevalence of class I (59% vs 45%) and class II (10% vs 7%) sarcopenia was greater in the older ( � 60 years) women than in the older men ( P � .001). The likelihood of functional impairment and disability was approximately two times greater in the older men and three times greater in the older women with class II sarcopenia than in the older men and women with a normal SMI, respectively. Some of the associations be- tween class II sarcopenia and functional impairment re- mained significant after adjustment for age, race, body mass index, health behaviors, and comorbidity. CONCLUSIONS: Reduced relative skeletal muscle mass in older Americans is a common occurrence that is signifi- cantly and independently associated with functional im- pairment and disability, particularly in older women. These observations provide strong support for the prevailing view that sarcopenia may be an important and potentially re- versible cause of morbidity and mortality in older persons. J Am Geriatr Soc 50:889-896, 2002.

Obesity and the Risk of Heart Failure

Abstract: Background Extreme obesity is recognized to be a risk factor for heart failure. It is unclear whether overweight and lesser degrees of obesity also pose a risk. Methods We investigated the relation between the body-mass index (the weight in kilograms divided by the square of the height in meters) and the incidence of heart failure among 5881 participants in the Framingham Heart Study (mean age, 55 years; 54 percent women). With the use of Cox proportional-hazards models, the body-mass index was evaluated both as a continuous variable and as a categorical variable (normal, 18.5 to 24.9; overweight, 25.0 to 29.9; and obese, 30.0 or more). Results During follow-up (mean, 14 years), heart failure developed in 496 subjects (258 women and 238 men). After adjustment for established risk factors, there was an increase in the risk of heart failure of 5 percent for men and 7 percent for women for each increment of 1 in body-mass index. As compared with subjects with a normal body-mass index, obese subjects had a do...

Overweight and obesity as determinants of cardiovascular risk: the Framingham experience.

Abstract: Background To our knowledge, no single investigation concerning the long-term effects of overweight status on the risk for hypertension, hypercholesterolemia, diabetes mellitus, and cardiovascular sequelae has been reported. Methods Relations between categories of body mass index (BMI), cardiovascular disease risk factors, and vascular disease end points were examined prospectively in Framingham Heart Study participants aged 35 to 75 years, who were followed up to 44 years. The primary outcome was new cardiovascular disease, which included angina pectoris, myocardial infarction, coronary heart disease, or stroke. Analyses compared overweight (BMI [calculated as weight in kilograms divided by the square of height in meters], 25.0-29.9) and obese persons (BMI ≥30) to a referent group of normal-weight persons (BMI, 18.5-24.9). Results The age-adjusted relative risk (RR) for new hypertension was highly associated with overweight status (men: RR, 1.46; women: RR, 1.75). New hypercholesterolemia and diabetes mellitus were less highly associated with excess adiposity. The age-adjusted RR (confidence interval [CI]) for cardiovascular disease was increased among those who were overweight (men: 1.21 [1.05-1.40]; women: 1.20 [1.03-1.41]) and the obese (men: 1.46 [1.20-1.77]; women: 1.64 [1.37-1.98]). High population attributable risks were related to excess weight (BMI ≥25) for the outcomes hypertension (26% men; 28% women), angina pectoris (26% men; 22% women), and coronary heart disease (23% men; 15% women). Conclusions The overweight category is associated with increased relative and population attributable risk for hypertension and cardiovascular sequelae. Interventions to reduce adiposity and avoid excess weight may have large effects on the development of risk factors and cardiovascular disease at an individual and population level.

A retrospective case-control analysis of 2002 running injuries

Abstract: Results: Most of the study group were women (54%). Some injuries occurred with a significantly higher frequency in one sex. Being less than 34 years old was reported as a risk factor across the sexes for patellofemoral pain syndrome, and in men for iliotibial band friction syndrome, patellar tendinopathy, and tibial stress syndrome. Being active for less than 8.5 years was positively associated with injury in both sexes for tibial stress syndrome; and women with a body mass index less than 21 kg/m 2 were at a significantly higher risk for tibial stress fractures and spinal injuries. Patellofemoral pain syndrome was the most common injury, followed by iliotibial band friction syndrome, plantar fasciitis, meniscal injuries of the knee, and tibial stress syndrome. Conclusions: Although various risk factors were shown to be positively associated with a risk for, or protection from, specific injuries, future research should include a non-injured control group and a more precise measure of weekly running distance and running experience to validate these results.

The Epidemiology of Obesity

Abstract: The epidemiology of obesity has for many years been difficult to study because many countries had their own specific criteria for the classification of different degrees of overweight. Gradually during the 1990s, however, the body mass index (BMI; weight/height ) became a universally accepted measure of the degree of overweight and now identical cut-points are recommended. This most recent classification of overweight in adults by the World Health Organization is shown in Table 2.1 (1). In many community studies in affluent societies this scheme has been simplified and cut-off points of 25 and 30 kg/m are used for descriptive purposes. The prevalence of very low BMI ( 18.5 kg/m ) and very high BMI (40 kg/m or higher) is usually low, in the order of 1—2% or less. Already researchers in Asian countries have criticized these cut-points. The absolute health risks seem to be higher at any level of the BMI in Chinese and South Asian people, which is probably also true for Asians living elsewhere. There are some developments that indicate that the cut-points to designate obesity or overweight may be lowered by several units of BMI. This would of course greatly affect the estimates of the prevalence of obesity in these populations. For instance, the prevalence of overweight measured as BMI 27 kg/m in the 1989 China Health and Nutrition Survey (2) was 6% in the North, 3% in Central China and 1% in the South. If the cut-off point was lowered to 25 kg/m the prevalence would be increased to, respectively, 15%, 9% and 6%. In countries such as China and India, each with over a billion inhabitants, small changes in the criteria for overweight or obesity potentially increase the world estimate of obesity by several hundred million (currently estimates are about 250 million worldwide). Much research over the last decade has suggested that for an accurate classification of overweight and obesity with respect to the health risks one needs to factor in abdominal fat distribution. Traditionally this has been indicated by a relatively high waist-tohip circumference ratio. Recently it has been accepted that the waist circumference alone may be a better and simpler measure of abdominal fatness (3,4). Table 2.2 gives some tentative cut-points for the waist circumference. These are again based on data in white populations. In June 1998 the National Institutes of Health (National Heart, Lung and Blood Institute) adopted the BMI classification and combined this with waist cut-off points (6). In this classification the combination of overweight (BMI between 25 and 30kg/m ) and moderate obesity (BMI between 30 and 35kg/m ) with a large waist circumference ( 102 cm inmen or 88 cm in women) is proposed to carry additional risk.

Predictors of sleep-disordered breathing in community-dwelling adults: the Sleep Heart Health Study.

Abstract: Background Sleep-disordered breathing (SDB) is common, but largely undiagnosed in the general population. Information on demographic patterns of SDB occurrence and its predictive factors in the general population is needed to target high-risk groups that may benefit from diagnosis. Methods The sample comprised 5615 community-dwelling men and women aged between 40 and 98 years who were enrolled in the Sleep Heart Health Study. Data were collected by questionnaire, clinical examinations, and in-home polysomnography. Sleep-disordered breathing status was based on the average number of apnea and hypopnea episodes per hour of sleep (apnea-hypopnea index [AHI]). We used multiple logistic regression modeling to estimate cross-sectional associations of selected participant characteristics with SDB defined by an AHI of 15 or greater. Results Male sex, age, body mass index, neck girth, snoring, and repeated breathing pause frequency were independent, significant correlates of an AHI of 15 or greater. People reporting habitual snoring, loud snoring, and frequent breathing pauses were 3 to 4 times more likely to have an AHI of 15 or greater vs an AHI less than 15, but there were weaker associations for other factors with an AHI of 15 or greater. The odds ratios (95% confidence interval) for an AHI of 15 or greater vs an AHI less than 15 were 1.6 and 1.5, respectively, for 1-SD increments in body mass index and neck girth. As age increased, the magnitude of associations for SDB and body habitus, snoring, and breathing pauses decreased. Conclusions A significant proportion of occult SDB in the general population would be missed if screening or case finding were based solely on increased body habitus or male sex. Breathing pauses and obesity may be particularly insensitive for identifying SDB in older people. A better understanding of predictive factors for SDB, particularly in older adults, is needed.

Asians are different from Caucasians and from each other in their body mass index/body fat per cent relationship

Abstract: Summary The objective was to study the relationship between body mass index (BMI) and body fat per cent (BF%) in different population groups of Asians. The study design was a literature overview with special attention to recent Asian data. Specific information is provided on Indonesians (Malays and Chinese ancestry), Singaporean Chinese, Malays and Indians, and Hong Kong Chinese. The BMI was calculated from weight and height and the BF% was determined by deuterium oxide dilution, a chemical-for-compartment model, or dual-energy X-ray absorptiometry. All Asian populations studied had a higher BF% at a lower BMI compared to Caucasians. Generally, for the same BMI their BF% was 3‐5% points higher compared to Caucasians. For the same BF% their BMI was 3‐4 units lower compared to Caucasians. The high BF% at low BMI can be partly explained by differences in body build, i.e. differences in trunk-to-leg-length ratio and differences in slenderness. Differences in muscularity may also contribute to the different BF%/BMI relationship. Hence, the relationship between BF% and BMI is ethnic-specific. For comparisons of obesity prevalence between ethnic groups, universal BMI cut-off points are not appropriate.

Dairy consumption, obesity, and the insulin resistance syndrome in young adults: The CARDIA study

Abstract: ContextComponents of the insulin resistance syndrome (IRS), including obesity, glucose intolerance, hypertension, and dyslipidemia, are major risk factors for type 2 diabetes and heart disease. Although diet has been postulated to influence IRS, the independent effects of dairy consumption on development of this syndrome have not been investigated.ObjectiveTo examine associations between dairy intake and incidence of IRS, adjusting for confounding lifestyle and dietary factors.DesignThe Coronary Artery Risk Development in Young Adults (CARDIA) study, a population-based prospective study.Setting and ParticipantsGeneral community sample from 4 US metropolitan areas of 3157 black and white adults aged 18 to 30 years who were followed up from 1985-1986 to 1995-1996.Main Outcome MeasureTen-year cumulative incidence of IRS and its association with dairy consumption, measured by diet history interview.ResultsDairy consumption was inversely associated with the incidence of all IRS components among individuals who were overweight (body mass index ≥25 kg/m2) at baseline but not among leaner individuals (body mass index <25 kg/m2). The adjusted odds of developing IRS (2 or more components) were 72% lower (odds ratio, 0.28; 95% confidence interval, 0.14-0.58) among overweight individuals in the highest (≥35 times per week, 24/102 individuals) compared with the lowest (<10 times per week, 85/190 individuals) category of dairy consumption. Each daily occasion of dairy consumption was associated with a 21% lower odds of IRS (odds ratio, 0.79; 95% confidence interval, 0.70-0.88). These associations were similar for blacks and whites and for men and women. Other dietary factors, including macronutrients and micronutrients, did not explain the association between dairy intake and IRS.ConclusionsDietary patterns characterized by increased dairy consumption have a strong inverse association with IRS among overweight adults and may reduce risk of type 2 diabetes and cardiovascular disease.

Validity of self-reported height and weight in 4808 EPIC-Oxford participants.

Abstract: Objective: To assess the validity of self-reported height and weight by comparison with measured height and weight in a sample of middle-aged men and women, and to determine the extent of misclassification of body mass index (BMI) arising from differences between self-reported and measured values. Design: Analysis of self-reported and measured height and weight data from participants in the Oxford cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC-Oxford). Subjects: Four thousand eight hundred and eight British men and women aged 35-76 years. Results: Spearman rank correlations between self-reported and measured height, weight and BMI were high (r > 0.9, P < 0.0001). Height was overestimated by a mean of 1.23 (95% confidence interval (CI) 1.11-1.34) cm in men and 0.60 (0.51-0.70) cm in women; the extent of overestimation was greater in older men and women, shorter men and heavier women. Weight was underestimated by a mean of 1.85 (1.72-1.99) kg in men and 1.40 (1.31-1.49) kg in women; the extent of underestimation was greater in heavier men and women, but did not vary with age or height. Using standard categories of BMI, 22.4% of men and 18.0% of women were classified incorrectly based on self-reported height and weight. After correcting the self-reported values using predictive equations derived from a 10% sample of subjects, misclassification decreased to 15.2% in men and 13.8% in women. Conclusions: Self-reported height and weight data are valid for identifying relationships in epidemiological studies. In analyses where anthropometric factors are the primary variables of interest, measurements in a representative sample of the study population can be used to improve the accuracy of estimates of height, weight and BMI.

Body mass index, waist circumference, and health risk: evidence in support of current National Institutes of Health guidelines.

Abstract: 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, ≤102 cm; women, ≤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.

Obesity Hypertension in Children. A Problem of Epidemic Proportions

Abstract: Obesity has become an increasingly important medical problem in children and adolescents. In national surveys from the 1960s to the 1990s, the prevalence of overweight in children grew from 5% to 11%. Outcomes related to childhood obesity include hypertension, type 2 diabetes mellitus, dyslipidemia, left ventricular hypertrophy, nonalcoholic steatohepatitis, obstructive sleep apnea, orthopedic problems, and psychosocial problems. Once considered rare, primary hypertension in children has become increasingly common in association with obesity and other risk factors, including a family history of hypertension and an ethnic predisposition to hypertensive disease. Obese children are at approximately a 3-fold higher risk for hypertension than nonobese children. In addition, the risk of hypertension in children increases across the entire range of body mass index (BMI) values and is not defined by a simple threshold effect. As in adults, a combination of factors including overactivity of the sympathetic nervous system (SNS), insulin resistance, and abnormalities in vascular structure and function may contribute to obesity-related hypertension in children. The benefits of weight loss for blood pressure reduction in children have been demonstrated in both observational and interventional studies. Obesity in childhood should be considered a chronic medical condition that is likely to require long-term management. Ultimately, prevention of obesity and its complications, including hypertension, is the goal.

A Prospective Study of the Role of Depression in the Development and Persistence of Adolescent Obesity

Abstract: Background. Adolescent obesity is a strong predictor of adult obesity, and adult obesity has been associated with depression, especially in women. Studies have also suggested an association between depression in adolescence and higher body mass index (BMI) in adulthood. Whether depression leads to obesity or obesity causes depression is unclear. Objective. To determine in longitudinal analyses whether depressed mood predicts the development and persistence of obesity in adolescents. Methods. A prospective cohort study of 9374 adolescents in grades 7 through 12 who completed in-home interviews for the National Longitudinal Study of Adolescent Health. Assessments were made at baseline (1995) and at follow-up 1 year later. Depressed mood was assessed with the Center for Epidemiologic Studies Depression Scale. BMI (kg/m2) was calculated from self-reported height and weight. BMI percentiles and z scores were computed using the 2000 Centers for Disease Control and Prevention growth charts. Obesity was defined as BMI ≥95th percentile, overweight as BMI ≥85th percentile and Results. At baseline, 12.9% were overweight, 9.7% were obese, and 8.8% had depressed mood. Baseline depression was not significantly correlated with baseline obesity. Among the 9.7% who were obese at follow-up, 79.6% were obese at baseline, 18.6% were overweight at baseline, and 1.8% were normal weight at baseline. Having depressed mood at baseline independently predicted obesity at follow-up (odds ratio: 2.05; 95% confidence interval: 1.18, 3.56) after controlling for BMI z score at baseline, age, race, gender, parental obesity, number of parents in the home, and family socioeconomic status. This finding persisted after controlling further for the adolescents’ report of smoking, self-esteem, delinquent behavior (conduct disorder), and physical activity. After controlling for all these same factors, depressed mood at baseline also predicted obesity at follow-up among those not obese at baseline (odds ratio: 2.05; 95% confidence interval: 1.04, 4.06) and follow-up BMI z score among those obese at baseline (β = 0.11; standard error β = 0.05). In contrast, baseline obesity did not predict follow-up depression. Conclusions. Depressed adolescents are at increased risk for the development and persistence of obesity during adolescence. Understanding the shared biological and social determinants linking depressed mood and obesity may inform the prevention and treatment of both disorders.

Sleep-disordered Breathing and Insulin Resistance in Middle-aged and Overweight Men

Abstract: Sleep-disordered breathing is a prevalent condition associated with impairment of daytime function and may predispose individuals to metabolic abnormalities independent of obesity. The primary objective of this study was to determine the metabolic consequences and community prevalence of sleep-disordered breathing in mildly obese, but otherwise healthy, individuals. One hundred and fifty healthy men, without diabetes or cardiopulmonary disease, were recruited from the community. Measurements included polysomnography, a multiple sleep latency test, an oral glucose tolerance test, determination of body fat by hydrodensitometry, and fasting insulin and lipids. The prevalence of sleep-disordered breathing, depending on the apnea-hypopnea index (AHI) cutoff, ranged from 40 to 60%. After adjusting for body mass index (BMI) and percent body fat, an AHI gt-or-equal, slanted 5 events/h was associated with an increased risk of having impaired or diabetic glucose tolerance (odds ratio, 2.15; 95% CI, 1.05-4.38). The impairment in glucose tolerance was related to the severity of oxygen desaturation (DeltaSa(O(2))) associated with sleep-disordered breathing. For a 4% decrease in oxygen saturation, the associated odds ratio for worsening glucose tolerance was 1.99 (95% CI, 1.11 to 3.56) after adjusting for percent body fat, BMI, and AHI. Multivariable linear regression analyses revealed that increasing AHI was associated with worsening insulin resistance independent of obesity. Thus, sleep-disordered breathing is a prevalent condition in mildly obese men and is independently associated with glucose intolerance and insulin resistance.

The Medical Risks of Obesity

Abstract: Obesity is associated with a number of medical conditions that lead to increased morbidity and increased mortality. Both the National Institutes of Health and the World Health Organization define obesity as a body mass index (BMI) > or = 30 kg/m2 and overweight as a BMI 25-30. The most common conditions associated with obesity are insulin resistance, diabetes mellitus, hypertension, dyslipidemia, cardiovascular disease, gallstones and cholecystitis, sleep apnea and other respiratory dysfunction, and the increased incidence of certain cancers. These are discussed below.

Metabolic syndrome and development of diabetes mellitus: application and validation of recently suggested definitions of the metabolic syndrome in a prospective cohort study.

Abstract: The World Health Organization (WHO) and the National Cholesterol Education Program (NCEP) recently proposed definitions for the metabolic syndrome. Little is known of their validity, however. The authors assessed the sensitivity and specificity of the definitions of the metabolic syndrome for prevalent and incident diabetes mellitus in a Finnish population-based cohort of middle-aged men (n = 1,005) followed for 4 years since the late 1980s. Four definitions based on the WHO and NCEP recommendations were compared. All definitions identified persons at high risk for developing diabetes during the 4-year follow-up (odds ratios = 5.0-8.8). The WHO definition including waist-hip ratio > 0.90 or body mass index >or= 30 kg/m(2) was the most sensitive (0.83 and 0.67) and least specific (0.78 and 0.80) in detecting the 47 prevalent and 51 incident cases of diabetes. The NCEP definition in which adiposity was defined as waist girth > 102 cm detected only 61% of prevalent and 41% of incident diabetes, although it was the most specific (0.89 and 0.90). The WHO definition seems valid as judged by its relatively high sensitivity and specificity in predicting diabetes. The NCEP definition including waist > 102 cm also identifies persons at high risk for diabetes, but it is relatively insensitive in predicting diabetes.

Prevalence of Sarcopenia and Predictors of Skeletal Muscle Mass in Healthy, Older Men and Women

Abstract: Background. Sarcopenia refers to the loss of skeletal muscle mass with age. The objective of this study was to determine the prevalence of sarcopenia in a population of older, community-dwelling research volunteers. Methods. Appendicular skeletal muscle mass was measured by dual x-ray absorptiometry in 195 women aged 64 to 93 years and 142 men aged 64 to 92 years. We defined sarcopenia as appendicular skeletal muscle mass/height 2 (square meters) less than 2 standard deviations below the mean for young, healthy reference populations. We used two different reference populations and compared prevalence in our population to that reported in previous studies. Body mass index (BMI) was calculated and physical activity and performance were measured with the Physical Activity Scale for the Elderly, the Short Physical Performance Battery, and the Physical Performance Test. We measured health-related quality of life by using the SF-36 general health survey. Serum estrone, estradiol, sex hormone-binding globulin, parathyroid hormone, and 25-hydroxy vitamin D were measured in all participants and bioavailable testosterone was measured only in men. Leg press strength and leg press power were determined in men. Results. The prevalence of sarcopenia in our cohort was 22.6% in women and 26.8% in men. A subgroup analysis of women and men 80 years or older revealed prevalence rates of 31.0% and 52.9%, respectively. In women, skeletal muscle mass correlated significantly with BMI and levels of serum estrone, estradiol, and 25-hydroxy vitamin D; in men, it correlated significantly with BMI, single leg stance time, leg press strength, leg press power, SF-36 general health score, Physical Performance Test total score, and bioavailable testosterone levels. With the use of linear regression analysis, BMI was the only predictor of appendicular skeletal muscle mass in women, accounting for 47.9% of the variance (p < .05). In men, BMI accounted for 50.1%, mean strength accounted for 10.3%, mean power accounted for 4.1%, and bioavailable testosterone accounted for 2.6% of the variance in appendicular skeletal muscle mass (p <.05). Conclusions. Sarcopenia is common in adults over the age of 65 years and increases with age. BMI is a strong predictor of skeletal muscle mass in women and men. Strength, power, and bioavailable testosterone are further contributors in men. These data suggest that interventions to target nutrition, strength training, and testosterone replacement therapy should be further investigated for their role in preventing muscle loss with age.

The Obesity Epidemic: Pathophysiology and Consequences of Obesity

Abstract: Obesity has reached epidemic proportions in the United States: more than 20% of adults are clinically obese as defined by a body mass index of 30 kg/m(2) or higher, and an additional 30% are overweight. Environmental, behavioral, and genetic factors have been shown to contribute to the development of obesity. Elevated body mass index, particularly caused by abdominal or upper-body obesity, has been associated with a number of diseases and metabolic abnormalities, many of which have high morbidity and mortality. These include hyperinsulinemia, insulin resistance, type 2 diabetes, hypertension, dyslipidemia, coronary heart disease, gallbladder disease, and certain malignancies. This underscores the importance of identifying people at risk for obesity and its related disease states.

Leg Muscle Mass and Composition in Relation to Lower Extremity Performance in Men and Women Aged 70 to 79: The Health, Aging and Body Composition Study

Abstract: OBJECTIVES: The loss of muscle mass with aging, or sarcopenia, is hypothesized to be associated with the deterioration of physical function. Our aim was to determine whether low leg muscle mass and greater fat infiltration in the muscle were associated with poor lower extremity performance (LEP). DESIGN: A cross-sectional study, using baseline data of the Health, Aging and Body Composition study (1997/98). SETTING: Medicare beneficiaries residing in ZIP codes from the metropolitan areas surrounding Pittsburgh, Pennsylvania, and Memphis, Tennessee. PARTICIPANTS: Three thousand seventy-five well-functioning black and white men and women aged 70 to 79. MEASUREMENTS: Two timed tests (6-meter walk and repeated chair stands) were used to measure LEP. Muscle cross-sectional area and muscle tissue attenuation (indicative of fat infiltration) were obtained from computed tomography scans at the midthigh. Body fat was assessed using dual-energy x-ray absorptiometry. RESULTS: Blacks had greater muscle mass and poorer LEP than whites. Black women had greater fat infiltration into the muscle than white women. After adjustment for clinic site, age, height, and total body fat, smaller muscle area was associated with poorer LEP in all four race-gender groups. (Regression coefficients, expressed per standard deviation (±55 cm2) of muscle area, were 0.658 and 0.519 in white and black men and 0.547 and 0.435 in white and black women, respectively, P .7) or between race and muscle attenuation (P> .2) were observed. CONCLUSION: Smaller midthigh muscle area and greater fat infiltration in the muscle are associated with poorer LEP in well-functioning older men and women.

Midthigh Muscle Cross-Sectional Area Is a Better Predictor of Mortality than Body Mass Index in Patients with Chronic Obstructive Pulmonary Disease

Abstract: This study was undertaken to test the hypothesis that a reduction in midthigh muscle cross-sectional area obtained by CT scan (MTCSACT) is a better predictor of mortality in chronic obstructive pulmonary disease (COPD) than low body mass index (BMI). We also wished to evaluate whether anthropometric measurements could be used to estimate MTCSACT. One hundred forty-two patients with COPD (age = 65 ± 9 years, mean ± SD, 26 F, BMI = 26 ± 6 kg/m2, FEV1 = 42 ± 16% predicted) were recruited from September 1995 to April 2000 with a mean follow-up of 41 ± 18 months. The primary end-point was all-cause mortality during the study period. A Cox proportional hazards regression model was used to predict mortality using the following independent variables: age, sex, daily use of corticosteroid, FEV1, DlCO, BMI, thigh circumference, MTCSACT, peak exercise workrate, PaO2, and PaCO2. Only MTCSACT and FEV1 were found to be significant predictors of mortality (p = 0.0008 and p = 0.01, respectively). A second analysis was al...

High-intensity resistance training improves glycemic control in older patients with type 2 diabetes.

Abstract: OBJECTIVE —To examine the effect of high-intensity progressive resistance training combined with moderate weight loss on glycemic control and body composition in older patients with type 2 diabetes. RESEARCH DESIGN AND METHODS —Sedentary, overweight men and women with type 2 diabetes, aged 60–80 years ( n = 36), were randomized to high-intensity progressive resistance training plus moderate weight loss (RT & WL group) or moderate weight loss plus a control program (WL group). Clinical and laboratory measurements were assessed at 0, 3, and 6 months. RESULTS —HbA1c fell significantly more in RT & WL than WL at 3 months (0.6 ± 0.7 vs. 0.07 ± 0.8%, P < 0.05) and 6 months (1.2 ± 1.0 vs. 0.4 ± 0.8%, P < 0.05). Similar reductions in body weight (RT & WL 2.5 ± 2.9 vs. WL 3.1 ± 2.1 kg) and fat mass (RT & WL 2.4 ± 2.7 vs. WL 2.7 ± 2.5 kg) were observed after 6 months. In contrast, lean body mass (LBM) increased in the RT & WL group (0.5 ± 1.1 kg) and decreased in the WL group (0.4 ± 1.0) after 6 months ( P < 0.05). There were no between-group differences for fasting glucose, insulin, serum lipids and lipoproteins, or resting blood pressure. CONCLUSIONS —High-intensity progressive resistance training, in combination with moderate weight loss, was effective in improving glycemic control in older patients with type 2 diabetes. Additional benefits of improved muscular strength and LBM identify high-intensity resistance training as a feasible and effective component in the management program for older patients with type 2 diabetes.

Summary health statistics for U.S. adults: National Health Interview Survey, 1997.

Abstract: This report presents health statistics from the 1997 National Health Interview Survey for the civilian noninstitutionalized adult population, classified by sex, age, race and Hispanic origin, poverty status, region of residence, and where appropriate, education, income, health insurance coverage, marital status, and place of residence. The topics covered are health status and limitations in activity, health care access and utilization, health behaviors and lifestyle, chronic condition prevalence, and knowledge and attitudes toward the Acquired Immunodeficiency Syndrome (AIDS). Source of Data The NHIS is a multistage probability sample survey conducted annually by interviewers of the U.S. Census Bureau for the National Center for Health Statistics, Centers for Disease Control and Prevention, and is representative of the civilian noninstitutionalized U.S. population. Data are collected during face-to-face interviews. Highlights Among adults 18 years of age or over, 12% had ever been told by a doctor or health professional that they had heart disease, 6% had ever been told they had coronary heart disease, and 19% had been told on two visits or more that they had hypertension. Nearly a quarter of adults were current smokers, 23% were former smokers, and 52% had never smoked. Sixty-one percent did not engage in any leisure-time vigorous physical activity, while approximately 24% engaged in such activity three times or more per week. Based on estimates of body mass index, 4% of adults were underweight, 42% were at a healthy weight, 35% were overweight, and 19% were obese.

Infant Weight Gain and Childhood Overweight Status in a Multicenter, Cohort Study

Abstract: Objective. To determine whether a rapid rate of weight gain in early infancy is associated with overweight status in childhood. Design. Prospective, cohort study from birth to age 7 years. Setting. Twelve sites across the United States. Participants. Twenty-seven thousand, eight hundred ninety-nine (27 899) eligible participants born at full term between 1959 and 1965. Main Outcome Measure. Overweight status at age 7 years, defined by a body mass index above the 95th percentile of the Centers for Disease Control and Prevention reference data. Results. In the 19 397 participants with complete data (69.6%), the prevalence of overweight status at age 7 years was 5.4%. The rate of weight gain during the first 4 months of life (as 100 g/month) was associated with being overweight at age 7 years, after adjustment for several confounding factors: odds ratio: 1.38; 95% confidence interval: 1.32–1.44. This association was present in each birth weight quintile, and remained significant after adjustment for the weight attained at age 1 year (odds ratio: 1.17; 95% confidence interval: 1.11–1.24). Conclusions. A pattern of rapid weight gain during the first 4 months of life was associated with an increased risk of overweight status at age 7 years, independent of birth weight and weight attained at age 1 year. These findings may lead to new hypotheses regarding the cause of childhood obesity, which may contribute to our understanding of this increasing public health problem in the United States.