Biomedical subjects

T B Harris

Publications and source records attributed to T B Harris.

At least 55 records · Page 3Linked to original sources

PubMed1998

Hip fracture risk in older white men is associated with change in body weight from age 50 years to old age.

BACKGROUND: Change in body weight is a potentially modifiable risk factor for hip fracture in older women but, to our knowledge, its relationship to risk in older men has not been reported previously. OBJECTIVE: To investigate the effects of weight loss and weight gain from age 50 years to old age on the risk of hip fracture among elderly men. METHODS: The association between weight change and risk of hip fracture was studied in a cohort of 2413 community-dwelling white men aged 67 years or older from 3 sites of the Established Populations for Epidemiologic Study of the Elderly. RESULTS: The older men in this study, observed for a total of 13620 person-years during the 8 years of follow-up, experienced 72 hip fractures, yielding an overall incidence rate of 5.3 per 1000 person-years. Extreme weight loss (> or =10%) beginning at age 50 years was associated in a proportional hazards model with increased risk of hip fracture (relative risk, 1.8; 95% confidence interval, 1.04-3.3). Weight loss of 10% or more was associated with several indicators of poor health, including physical disability, low mental status score, and low physical activity (P<.05). Weight gain of 10% or more beginning at age 50 years provided borderline protection against the risk of hip fracture (relative risk, 0.4; 95% confidence interval, 0.1-1.00). CONCLUSIONS: Despite differences between older men and women in the incidence of and risk factors for hip fracture, weight history is also an important determinant of the risk of hip fracture among older men. Weight loss of 10% or more beginning at age 50 years increases the risk of hip fracture in older white men; weight gain of 10% or more decreases the risk of hip fracture. The relationship between extreme weight loss and poor health suggests that weight loss is a marker of frailty that may increase the risk of hip fracture in older men. Physicians should include weight history in their assessment of the risk of hip fracture among older men.

Aged↗

PubMed1998

Updated data on proximal femur bone mineral levels of US adults.

This paper describes data on bone mineral levels in the proximal femur of US adults based on the nationally representative sample examined during both phases of the third National Health and Nutrition Examination Survey (NHANES III, 1988-94), and updates data previously presented from phase 1 only. The data were collected from 14,646 men and women aged 20 years and older using dual-energy X-ray absorptiometry, and included bone mineral density (BMD), bone mineral content (BMC) and area of bone scanned in four selected regions of interest (ROI) in the proximal femur: femur neck, trochanter, intertrochanter and total. These variables are provided separately by age and sex for non-Hispanic whites (NHW), non-Hispanic blacks (NHB) and Mexican Americans (MA). NHW in the southern United States had slightly lower BMD levels than NHW in other US regions, but these differences were not sufficiently large to prevent pooling of the data. The updated data provide valuable reference data on femur bone mineral levels of noninstitutionalized adults. The updated data on BMD for the total femur ROI of NHW have been selected as the reference database for femur standardization efforts by the International Committee on Standards in Bone Measurements.

Absorptiometry, Photon↗

PubMed1998

High body fatness, but not low fat-free mass, predicts disability in older men and women: the Cardiovascular Health Study.

Using data from the Cardiovascular Health Study, we studied the relation between body composition (fat mass and fat-free mass, assessed by bioelectrical impedance) and self-reported, mobility-related disability (difficulty walking or stair climbing) in 2714 women and 2095 men aged 65-100 y. In a cross-sectional analysis at baseline (1989-1990), disability was reported by 26.5% of the women and 16.9% of the men. A positive association was observed between fat mass and disability. The odds ratio for disability in the highest quintile of fat mass was 3.04 (95% CI: 2.18, 4.25) for women and 2.77 (95% CI: 1.82, 4.23) for men compared with those in the lowest quintile. Low fat-free mass was not associated with a higher prevalence of disability. In a longitudinal analysis among persons not reporting disability at baseline, 20.3% of the women and 14.8% of the men reported disability 3 y later. Fat mass at baseline was predictive of disability 3 y later, with odds ratios of 2.83 (95% CI: 1.80, 4.46) for women and 1.72 (95% CI: 1.03, 2.85) for men in the highest quintile of fat. The increased risk was not explained by age, physical activity, chronic disease, or other potential confounders. Low fat-free mass was not predictive of disability. The results showed that high body fatness is an independent predictor of mobility-related disability in older men and women. These findings suggest that high body fatness in old age should be avoided to decrease the risk of disability.

Adipose Tissue↗

PubMed1998

Monocyte cytokine production in an elderly population: effect of age and inflammation.

OBJECTIVE: To determine the association among aging, inflammation, and cytokine production by peripheral blood mononuclear cells. POPULATION AND METHODS: We examined production of interleukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), IL-1 receptor antagonist (IL-1Ra), and IL-6 in 711 elderly participants in the Framingham Heart Study (mean age, 79 y) and 21 young healthy volunteers (mean age, 39 y). The elderly subjects were categorized by serum C-reactive protein (CRP) concentration, a marker of systemic inflammation. RESULTS: Production of IL-6 (p < .00001) and IL-1Ra (p < .00001) was higher in the elderly subjects than in the control group. IL-6 production increased with increasing CRP, whereas IL-1RA was uniformly elevated in elderly subjects regardless of CRP. However, we found no difference in the production of IL-1 beta or TNF-alpha between the young and elderly groups, regardless of CRP status. IL-6 population correlated with IL-1 beta (r = .36, p < .0001) and TNF-alpha production (r = .25, p < .0001), but IL-1Ra production did not. CONCLUSION: Production of IL-6 and IL-1Ra--but not IL-1 beta or TNF-alpha--was increased in the elderly compared to healthy, young subjects. The increase in IL-6 also correlated with increased production of CRP, a marker of inflammation. However, IL-1Ra was increased in the elderly independently of CRP production. Although limited by the small control group, these data suggest that dysregulation of some inflammatory cytokines occurs with age, but the role of inflammation in aging remains unclear.

Adult↗

PubMed1998

Body fat and skeletal muscle mass in relation to physical disability in very old men and women of the Framingham Heart Study.

BACKGROUND: Low muscle mass has been assumed to be associated with disability, but no studies confirming this association have been published. High body weight and high body mass index, both rough indicators of body fatness, have been shown to increase the risk for disability; however, the specific role of body fatness has not been studied. METHODS: The relations of skeletal muscle mass and percent body fat with self-reported physical disability were studied in 753 men and women aged 72 to 95 years. Cross-sectional data from biennial examination 22 (1992-1993) of the Framingham Heart Study were used. Body composition was assessed by dual-energy x-ray absorptiometry. Disability was scored as any versus none on a 9-item questionnaire. RESULTS: Total body and lower extremity muscle mass were not associated with disability in either men or women. However, a strong positive association between percent body fat and disability was observed. The odds ratio for disability in those in the highest tertile of body fatness was 2.69 (95% confidence interval 1.45-5.00) for women and 3.08 (1.22-7.81) for men compared to those in the lowest tertile. The increased risk could not be explained by age, education, physical activity, smoking, alcohol use, estrogen use (women only), muscle mass, and health status. Analyses restricting disability to mobility items gave similar results. CONCLUSIONS: In contrast to current assumptions, low skeletal muscle mass was not associated with self-reported physical disability. Persons with a high percent body fat had high levels of disability. Because it cannot be ruled out that persons with low skeletal muscle mass dropped out earlier in the study, prospective studies are needed to further assess the relationship between body composition and physical disability.

Absorptiometry, Photon↗

PubMed1998

Body mass index and mortality in nonsmoking older adults: the Cardiovascular Health Study.

OBJECTIVES: This study assesses the relationship of body mass index to 5-year mortality in a cohort of 4317 nonsmoking men and women aged 65 to 100 years. METHODS: Logistic regression analyses were conducted to predict mortality as a function of baseline body mass index, adjusting for demographic, clinical, and laboratory covariates. RESULTS: There was an inverse relationship between body mass index and mortality; death rates were higher for those who weighed the least. Inclusion of covariates had trivial effects on these results. People who had lost 10% or more of their body weight since age 50 had a relatively high death rate. When that group was excluded, there was no remaining relationship between body mass index and mortality. CONCLUSIONS: The association between higher body mass index and mortality often found in middle-aged populations was not observed in this large cohort of older adults. Over-weight does not seem to be a risk factor for 5-year mortality in this age group. Rather, the risks associated with significant weight loss should be the primary concern.

Age Distribution↗

PubMed1998

Ten-year prediction of women's drinking behavior in a nationally representative sample.

This study evaluates how well women's personal and social characteristics predict their drinking behavior over a 10-year period, using data from a national representative sample of 696 U.S. women interviewed in 1981 and 1991. Interviews obtained data on drinking behavior, personality characteristics, childhood and recent experiences, and perceptions of the social environment. Analyses using paired comparisons, correlations, and linear and logistic regression found that women's alcohol use and its adverse consequences in 1991 were predicted by age, 1981 drinking behavior, and many other aspects of their lives measured 10 years before. Heavier and riskier drinking patterns were associated in particular with adverse childhood experiences, missing interpersonal ties, and expected self-expressive benefits of drinking. However, no variables predicted all patterns of drinking behavior, and specific predictors of different drinking patterns showed little overlap. We conclude that many aspects of women's lives, and particularly their interpersonal relationships, have long-term influences on their drinking behavior, but different patterns of drinking behavior have different antecedents.

Adult↗

PubMed1997

Cohort study of effect of being overweight and change in weight on risk of coronary heart disease in old age.

OBJECTIVE: To evaluate risk of late life coronary heart disease associated with being overweight in late middle or old age and to assess whether weight change modifies this risk. DESIGN: Longitudinal study of subjects in the epidemiological follow up study of the national health and nutrition examination survey I. SETTING: United States. SUBJECTS: 621 men and 960 women free of coronary heart disease in 1982-84 (mean age 77 years). MAIN OUTCOME MEASURE: Incidence of coronary heart disease. RESULTS: Body mass index of 27 or more in late middle age was associated with increased risk of coronary heart disease in late life (relative risk = 1.7 (95% confidence interval 1.3 to 2.1)) while body mass index of 27 or more in old age was not (1.1 (0.8 to 1.5)). This difference in risk was due largely to weight loss between middle and old age. Exclusion of those with weight loss of 10% or more increased risk associated with heavier weight in old age (1.4 (1.0 to 1.9)). Thinner older people who lost weight and heavier people who had gained weight showed increased risk of coronary heart disease compared with thinner people with stable weight. CONCLUSIONS: Heavier weight in late middle age was a risk factor for coronary heart disease in late life. Heavier weight in old age was associated with an increased risk once those with substantial weight loss were excluded. The contribution of weight to risk of coronary heart disease in older people may be underestimated if weight history is neglected.

Adult↗

PubMed1997

Smoking history in middle age and subsequent cognitive performance in elderly Japanese-American men. The Honolulu-Asia Aging Study.

The associations between cigarette smoking history and later cognitive performance were examined among 3,429 Japanese-American participants of the Honolulu Heart Program (HHP) and its extension, the Honolulu-Asia Aging Study (HAAS). Cognitive performance was measured by the Cognitive Abilities Screening Instrument (CASI), administered as part of HAAS (mean age at HAAS exam (standard deviation (SD)): 77.7 (4.6) years). Information on smoking history was collected during the first and third HHP exams (mean age (SD) at Exam III: 58.6 (4.7) years). Compared with never-smokers, those who had smoked continuously between Exams I-III and those who had quit smoking during that period had significantly lower CASI scores, after adjustment for age, education, Japanese acculturation, and Exam III alcohol intake. In multiple logistic regression controlling for the above covariates, a significantly higher risk of cognitive impairment (CASI score < 82) was associated with continuous smoking (odds ratio (OR) = 1.36, 95% confidence interval (CI) 1.10-1.69) and quitting between Exams I-III (OR = 1.36, 95% CI 1.03-1.80) compared with never smoking. This excess risk of cognitive impairment among continuous smokers and Exam I-III quitters was slightly diminished by further adjustment for body mass index and several vascular covariates. Additional analyses suggested a reduced risk of cognitive impairment among the longer-term quitters. This study suggests a positive association between smoking during middle age and later risk of cognitive impairment.

Aged↗

PubMed1997

Carrying the burden of cardiovascular risk in old age: associations of weight and weight change with prevalent cardiovascular disease, risk factors, and health status in the Cardiovascular Health Study.

Measured weight in old age, reported weight at age 50 y, and weight change from age 50 y to old age were studied in association with prevalent cardiovascular disease (CVD), CVD risk factors, and health status in a population of 4954 men and women aged > or = 65 y in the Cardiovascular Health Study (CHS). Heavier weight (i.e., generally weight in the fourth quartile for the cohort) at age 50 y was more closely associated with prevalent CVD than was current weight, with these associations stronger in women than in men. Heavier current weight and heavier weight at age 50 y were associated with cardiovascular risk factors, including higher blood pressure, lower high-density-lipoprotein cholesterol, and higher fasting insulin. Heavier weight at both time points was related to mobility problems in both men and women and to lower current physical activity levels; among women, strong associations were also seen with lower education and current income. Remaining within 10% of reported weight at age 50 y was associated with better health status as measured by reported health, mobility difficulty, number of medications, and prevalent CVD in men. Paradoxically, most cardiovascular risk factors were lowest for weight losers despite an association of weight loss with poorer health. In this cohort of persons aged > or = 65 y, heavier weight was associated with CVD and CVD risk factors, suggesting that prevention of overweight may prove beneficial in improving cardiovascular risk in older persons. Weight stability from age 50 y to old age was associated with better health status than was weight gain or loss.

Aged↗

PubMed1997

Application of bioelectrical impedance analysis to elderly populations.

BACKGROUND: Bioelectrical impedance analysis (BIA) can potentially be used to estimate body composition in large populations studied at multiple sites. However, it is not clear whether age-specific BIA equations are necessary for accurate application of BIA to research on elderly subjects. METHODS: We compared a published equation designed to predict fat-free mass (FFM) that had been derived in a young healthy population (mean age 27 y; mean BMI 23.9 kg/m2), with equations that we developed for the elderly by using data from 455 participants in the Framingham Heart Study (78 Y; 27.3 kg/m2), using dual-energy x-ray absorptiometry (DXA) as a reference technique. The BIA equations were then compared in an independent sample of 283 participants in the New Mexico Aging Process Study (76 y, 25.5 kg/m2), who also underwent BIA and DXA. RESULTS: When the young-population equation was applied to Framingham, it caused an overestimation of FFM in heavier subjects that was eliminated by use of the age-specific equation. However, when the two equations were tested in the New Mexico population, the published equation gave estimates of FFM that were closer to DXA than the Framingham equations did. CONCLUSIONS: The accuracy of a BIA equation depends on the body composition of the population of the population and the validation method rather than on age per se. Application of BIA to elderly populations requires uniform validation procedures in the actual study population, rather than reliance on age-specific equations.

Absorptiometry, Photon↗

PubMed1997

Association of insulin-like growth factor-I with body composition, weight history, and past health behaviors in the very old: the Framingham Heart Study.

OBJECTIVES: We examined correlates of insulin-like growth factor-I (IGF-I), an indicator of growth hormone levels, to identify factors associated with higher levels of IGF-I in old age. DESIGN: Nested study of cross-sectional correlates and early-life predictors of IGF-I level. SETTING: A longitudinal cohort study, the Framingham Heart Study. PARTICIPANTS: A total of 790 men and women (mean age 78.5, range 72-94), who had weight, waist and hip circumferences measured at the time of IGF-I measurement. MEASUREMENTS: Association of IGF-I with weight, fat distribution, functional status, nutritional indicators, and past health behaviors was assessed. We also examined IGF-I in relation to body composition derived from dual energy X-ray absorptiometry. RESULTS: IGF-I levels declined with age in both men and women. However, low IGF-I did not show expected associations with low lean mass and increased body fat. Current functional status and grip strength were not associated with IGF-I Low IGF-I was associated with weight loss in men; the strongest associations were with indicators of poorer nutritional status in both men and women. Levels of IGF-I in old age did not vary by past health behaviors. CONCLUSION: Although IGF-I declined with age, these data from the Framingham Heart Study did not show expected cross-sectional associations of weight, body fat, and lean mass. The strongest associations were between IGF-I and nutritional indicators. These results suggest caution may be warranted with regard to use of IGF-I as an indicator of growth hormone.

Aged↗

PubMed1997

Prevalence of low femoral bone density in older U.S. adults from NHANES III.

Most estimates of osteoporosis in older U.S. adults have been based on its occurrence in white women, even though it is known to affect men and minority women. In the present study, we used dual-energy X-ray absorptiometry measurements of femoral bone mineral density (BMD) from the third National Health and Nutrition Examination Survey (NHANES III, 1988-1994) to estimate the overall scope of the disease in the older U.S. population. Specifically, we estimate prevalences of low femoral BMD in women 50 years and older and explore different approaches for defining low BMD in older men in that age range. Low BMD levels were defined in accordance with an approach proposed by an expert panel of the World Health Organization and used BMD data from 382 non-Hispanic white (NHW) men or 409 NHW women ages 20-29 years from the NHANES III dataset. For women, estimates indicate 13-18%, or 4-6 million, have osteoporosis (i.e., BMD > 2.5 standard deviations [SD] below the mean of young NHW women) and 37-50%, or 13-17 million, have osteopenia (BMD between 1 and 2.5 SD below the mean of young NHW women). For men, these numbers depend on the gender of the reference group used to define cutoff values. When based on male cutoffs, 3-6% (1-2-million) of men have osteoporosis and 28-47% (8-13 million) have osteopenia; when based on female cutoffs, 1-4% (280,000-1 million) have osteoporosis and 15-33% (4-9 million) have osteopenia. Most of the older U.S. adults with low femur BMD are women, but, regardless of which cutoffs are used, the number of men is substantial.

Absorptiometry, Photon↗

PubMed1997

Failure to thrive, sacropenia and functional decline in the elderly.

At this time, there are no commonly accepted definitions for either the "failure to thrive" syndrome or for the newly described syndrome of sarcopenia. This lack of a common definition makes it difficult to contrast study results and understand the etiology of these syndromes. This article reviews the current state of understanding of these conditions and suggests potential mechanisms that may be further investigated.

Aged↗

PubMed1996

Vitamin E and vitamin C supplement use and risk of all-cause and coronary heart disease mortality in older persons: the Established Populations for Epidemiologic Studies of the Elderly.

We examined vitamin E and vitamin C supplement use in relation to mortality risk and whether vitamin C enhanced the effects of vitamin E in 11,178 persons aged 67-105 y who participated in the Established Populations for Epidemiologic Studies of the Elderly in 1984-1993. Participants were asked to report all nonprescription drugs currently used, including vitamin supplements. Persons were defined as users of these supplements if they reported individual vitamin E and/or vitamin C use, not part of a multivitamin. During the follow-up period there were 3490 deaths. Use of vitamin E reduced the risk of all-cause mortality [relative risk (RR) = 0.66; 95% CI: 0.53, 0.83] and risk of coronary disease mortality (RR = 0.53; 95% CI: 0.34, 0.84). Use of vitamin E at two points in time was also associated with reduced risk of total mortality compared with that in persons who did not use any vitamin supplements. Effects were strongest for coronary heart disease mortality (RR = 0.37; 95% CI: 0.15, 0.90). The RR for cancer mortality was 0.41 (95% CI: 0.15, 1.08). Simultaneous use of vitamins E and C was associated with a lower risk of total mortality (RR = 0.58; 95% CI: 0.42, 0.79) and coronary mortality (RR = 0.47; 95% CI: 0.25, 0.87). Adjustment for alcohol use, smoking history, aspirin use, and medical conditions did not substantially alter these findings. These findings are consistent with those for younger persons and suggest protective effects of vitamin E supplements in the elderly.

Aged↗

PubMed1995

Does weight loss from middle age to old age explain the inverse weight mortality relation in old age?

The authors examined body mass index at middle age, body mass index in old age, and weight change between age 50 years and old age in relation to mortality in old age. The study population from the Established Populations for Epidemiologic Studies of the Elderly consisted of 6,387 whites age 70 years or older who experienced 2,650 deaths during the period 1982-1987. Mortality risk was highest for persons in the heaviest quintile of body mass index at age 50 (men, relative risk (RR) = 1.33, 95% confidence interval (CI) 1.13-1.57; women, RR = 1.31, 95% CI 1.12-1.53) compared with persons in the middle quintile. This pattern was reversed for body mass index in old age, with persons in the lowest quintile having the highest mortality risk (men, RR = 1.40, 95% CI 1.19-1.65; women, RR = 1.38, 95% CI 1.17-1.63) relative to persons in the middle quintile. This reversal was explained, in part, by weight change. Compared with persons with stable weight, those who lost 10 percent or more of body weight between age 50 and old age had the highest risk of mortality (men, RR = 1.69, 95% CI 1.45-1.97; women, RR = 1.62, 95% CI 1.38-1.90). Exclusion of participants who lost 10 percent or more of their weight and adjustment for health status eliminated the higher risk of death associated with low weight. The inverse association of weight and mortality in old age appears to reflect illness-related weight loss from heavier weight in middle-age. Weight history may be critical to understanding weight and mortality relations in old age.

Aged↗

PubMed1995

Prevalence of low femoral bone density in older U.S. women from NHANES III.

Data on the number of U.S. women with low femoral bone mineral density (BMD) are currently available only from indirect estimates. We used dual-energy X-ray absorptiometry (DXA) measurements of femoral BMD from phase 1 of the third National Health and Nutrition Examination Survey (NHANES III, 1988-1991) to estimate prevalences of low femoral BMD in women ages 50 years and older using an approach proposed recently by an expert panel of the World Health Organization (WHO). Cutpoints for low BMD were derived from BMD data of 194 non-Hispanic white (NHW) women aged 20-29 years from the NHANES III dataset. The prevalence of older U.S. women with femoral osteopenia (BMD between 1 standard deviation [SD] and 2.5 SD below the mean of young NHW women) ranged from 34-50% in four different femur regions, which corresponds to approximately 12-17 million women. The prevalence with osteoporosis (BMD > 2.5 SD below the mean of young NHW women) ranged from 17-20%, or approximately 6-7 million women. Prevalences were 1.3-2.4 times higher in NHW women than non-Hispanic black women (NHB), and 0.8-1.2 times higher in NHW versus Mexican American (MA) women. The estimated numbers of NHW, NHB, and MA women with osteopenia were 10-15 million, 800,000-1.2 million, and 300,000-400,000, respectively; corresponding figures for osteoporosis were 5-6 million, 200,000-300,000, and 100,000 respectively. Thus, the first data on BMD from a nationally representative sample of older women show a substantial number with low femoral BMD.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗

PubMed1995

Proximal femur bone mineral levels of US adults.

This paper describes bone mineral levels in the proximal femur of US adults based on a nationally representative sample of 7116 men and women aged 20 years and older. The data were collected in phase 1 of the third National Health and Nutrition Examination Survey (NHANES III, 1988-1991) using dual-energy X-ray absorptiometry, and included bone mineral density (BMD), bone mineral content (BMC) and area of bone scanned in five selected regions of interest (ROI) in the proximal femur: femur neck, trochanter, intertrochanter, Ward's triangle and total. These variables are provided separately by age and sex for non-HIspanic whites (NHW), non-Hispanic blacks (NHB) and Mexican Americans (MA). BMD and BMC in the five ROI tended to decline with age, whereas area did not. BMD and BMC were highest in NHB, intermediate in MA and lowest in NHW, but areas were highest in NHW, intermediate in NHB and lowest in MA. Men had greater BMD, BMC and area than women in all three race/ethnic groups. Differences by age, sex or race/ethnicity tended to be the largest in Ward's triangle, followed by the femur neck; patterns in the trochanter, intertrochanter and total ROI were reasonably similar to each other. This report provides extensive data on femur bone mineral levels of adults from one of the largest samples available to date and should be valuable as reference data for other studies which examine this skeletal site in adults.

Adult↗