How useful is body mass index for comparison of body fatness across age, sex, and ethnic groups?

This study tested the hypothesis that body mass index (BMI) is representative of body fatness independent of age, sex, and ethnicity. Between 1986 and 1992, the authors studied a total of 202 black and 504 white men and women who resided in or near New York City, were ages 20-94 years, and had BMIs of 18-35 kg/m2. Total body fat, expressed as a percentage of body weight (BF%), was assessed using a four-compartment body composition model that does not rely on assumptions known to be age, sex, or ethnicity dependent. Statistically significant age dependencies were observed in the BF%-BMI relations in all four sex and ethnic groups (p values < 0.05-0.001) with older persons showing a higher BF% compared with younger persons with comparable BMIs. Statistically significant sex effects were also observed in BF%-BMI relations within each ethnic group (p values < 0.001) after controlling first for age. For an equivalent BMI, women have significantly greater amounts of total body fat than do men throughout the entire adult life span. Ethnicity did not significantly influence the BF%-BMI relation after controlling first for age and sex even though both black women and men had longer appendicular bone lengths relative to stature (p values < 0.001 and 0.02, respectively) compared with white women and men. Body mass index alone accounted for 25% of between-individual differences in body fat percentage for the 706 total subjects; adding age and sex as independent variables to the regression model increased the variance (r2) to 67%. These results suggest that BMI is age and sex dependent when used as an indicator of body fatness, but that it is ethnicity independent in black and white adults.

Appendicular skeletal muscle mass: effects of age, gender, and ethnicity

This study tested the hypothesis that skeletal muscle mass is reduced in elderly women and men after adjustment first for stature and body weight. The hypothesis was evaluated by estimating appendicular skeletal muscle mass with dual-energy X-ray absorptiometry in a healthy adult cohort. A second purpose was to test the hypothesis that whole body 40K counting-derived total body potassium (TBK) is a reliable indirect measure of skeletal muscle mass. The independent effects on both appendicular skeletal muscle and TBK of gender (n = 148 women and 136 men) and ethnicity (n = 152 African-Americans and 132 Caucasians) were also explored. Main findings were 1) for both appendicular skeletal muscle mass (total, leg, and arm) and TBK, age was an independent determinant after adjustment first by stepwise multiple regression for stature and weight (multiple regression model r2 = approximately 0.60); absolute decrease with greater age in men was almost double that in women; significantly larger absolute amounts were observed in men and African-Americans after adjustment first for stature, weight, and age; and >80% of within-gender or -ethnic group between-individual component variation was explained by stature, weight, age, gender, and ethnicity differences; and 2) most of between-individual TBK variation could be explained by total appendicular skeletal muscle (r2 = 0.865), whereas age, gender, and ethnicity were small but significant additional covariates (total r2 = 0.903). Our study supports the hypotheses that skeletal muscle is reduced in the elderly and that TBK provides a reasonable indirect assessment of skeletal muscle mass. These findings provide a foundation for investigating skeletal muscle mass in a wide range of health-related conditions.

Inflammatory markers and cognition in well-functioning African-American and white elders

BACKGROUND

Several lines of evidence suggest that inflammatory mechanisms contribute to AD.

OBJECTIVE

To examine whether several markers of inflammation are associated with cognitive decline in African-American and white well-functioning elders.

METHODS

The authors studied 3,031 African-American and white men and women (mean age 74 years) enrolled in the Health, Aging, and Body Composition Study. Serum levels of interleukin-6 (IL-6) and C-reactive protein (CRP) and plasma levels of tumor necrosis factor-alpha (TNFalpha) were measured at baseline; cognition was assessed with the Modified Mini-Mental State Examination (3MS) at baseline and at follow-up. Cognitive decline was defined as a decline of >5 points.

RESULTS

In age-adjusted analyses, participants in the highest tertile of IL-6 or CRP performed nearly 2 points lower (worse) on baseline and follow-up 3MS (p < 0.001 for all) and declined by almost 1 point over the >2 years (p = 0.01 for IL-6 and p = 0.04 for CRP) compared with those in the lowest tertile. After multivariate adjustment, 3MS scores among participants in the highest tertile of IL-6 and CRP were similar at baseline but remained significantly lower at follow-up (p < or = 0.05 for both). Those in the highest inflammatory marker tertile were also more likely to have cognitive decline compared with the lowest tertile for IL-6 (26 vs 20%; age-adjusted odds ratio [OR] = 1.34; 95% CI 1.06 to 1.69) and for CRP (24 vs 19%; OR = 1.41; 95% CI 1.10 to 1.79) but not for TNFalpha (23 vs 21%; OR = 1.12; 95% CI 0.88 to 1.43). There was no significant interaction between race and inflammatory marker or between nonsteroidal anti-inflammatory drug use and inflammatory marker on cognition.

CONCLUSIONS

Serum markers of inflammation, especially IL-6 and CRP, are prospectively associated with cognitive decline in well-functioning elders. These findings support the hypothesis that inflammation contributes to cognitive decline in the elderly.

Muscle strength and body mass index as long-term predictors of mortality in initially healthy men

BACKGROUND

Muscle weakness, low body weight, and chronic diseases are often observed in the same people; however, the association of muscle strength with mortality, independent of disease status and body weight, has not been elucidated. The aim was to assess hand grip strength as a predictor of all-cause mortality within different levels of body mass index (BMI) in initially disease-free men.

METHODS

Mortality was followed prospectively over 30 years. Maximal hand grip strength tests and BMI assessments were done at baseline in 1965 to 1970. The participants were 6040 healthy men aged 45 to 68 years at baseline living on Oahu, Hawaii.

RESULTS

The death rates per 1000 person years were 24.6 in those with BMI <20, 18.5 in the middle BMI category, and 18.0 in those with BMI > or = 25. For grip strength tertiles, the mortality rates were 24.8 in the lowest, 18.5 in the middle, and 14.0 in the highest third. In Cox regression models, within each tertile of grip strength, BMI showed only minimal effect on mortality. In contrast, in each category of BMI there was a gradient of decreasing mortality risk with increasing grip strength. Among those with BMI <20, the adjusted relative risks (RRs) of mortality over 30 years were 1.36 (95% confidence interval 1.14-1.63) for those in the lowest third of strength at baseline, 1.27 (1.02-1.58) in the middle, and 0.92 (0.66-1.29) in the highest third. Correspondingly, for those with BMI 20-24.99, the RRs of death were 1.25 (1.08-1.45), 1.14 (1.00-1.32), and 1.0 (reference) in the lowest, middle, and highest third of grip strength, respectively. In those with BMI > or =25, the RRs were 1.39 (1.16-1.65) in the lowest, 1.27 (1.08-1.49) in the middle, and 1.14 (0.98-1.32) in the highest third of grip strength. Models were adjusted for age, education, occupation, smoking, physical activity, and body height.

CONCLUSIONS

In healthy middle-aged men, long-term mortality risk was associated with grip strength at baseline, independent of BMI. The possible interpretation of the finding is that early life influences on muscle strength may have long-term implications for mortality. Additionally, higher strength itself may provide greater physiologic and functional reserve that protects against mortality.

Weight change in old age and its association with mortality

OBJECTIVES

Previous studies of weight change and mortality in older adults have relied on self-reported weight loss, have not evaluated weight gain, or have had limited information on health status. Our objective was to determine whether 5% weight gain or loss in 3 years was predictive of mortality in a large sample of older adults.

DESIGN

Longitudinal observational cohort study.

SETTING

Four U.S. communities.

PARTICIPANTS

Four thousand seven hundred fourteen community-dwelling older adults, age 65 and older.

MEASUREMENTS

Weight gain or loss of 5% in a 3-year period was examined in relationship to baseline health status and interim health events. Risk for subsequent mortality was estimated in those with weight loss or weight gain compared with the group whose weight was stable.

RESULTS

Weight changes occurred in 34.6% of women and 27.3% of men, with weight loss being more frequent than gain. Weight loss was associated with older age, black race, higher weight, lower waist circumference, current smoking, stroke, any hospitalization, death of a spouse, activities of daily living disability, lower grip strength, and slower gait speed. Weight loss but not weight gain of 5% or more was associated with an increased risk of mortality that persisted after multivariate adjustment (Hazard ratio (HR) = 1.67, 95% CI = 1.29-2.15) and was similar in those with no serious illness in the period of weight change. Those with weight loss and low baseline weight had the highest crude mortality rate, although the HR for weight loss was similar for all tertiles of baseline weight and for those with or without a special diet, compared with those whose weight was stable.

CONCLUSIONS

This study confirms that even modest decline in body weight is an important and independent marker of risk of mortality in older adults.

Interleukin-6 and risk of cognitive decline: MacArthur studies of successful aging

OBJECTIVE

To investigate whether plasma interleukin-6 (IL-6) is cross-sectionally related to poorer cognitive function and whether a baseline plasma IL-6 measurement can predict risk for decline in cognitive function in longitudinal follow-up of a population-based sample of nondisabled elderly people.

METHODS

A prospective cohort study of 779 high-functioning men and women aged 70 to 79 from the MacArthur Study of Successful Aging was conducted. Regression modeling was used to investigate whether baseline IL-6 levels (classified by tertiles) were associated with initial cognitive function and whether IL-6 levels predicted subsequent declines in cognitive function from 1988 to 1991 (2.5-year follow-up) and from 1988 to 1995 (7-year follow-up).

RESULTS

Subjects in the highest tertile for plasma IL-6 were marginally more likely to exhibit poorer baseline cognitive function (i.e., scores below the median), independent of demographic status, social status, health and health behaviors, and other physiologic variables (odds ratio [OR] = 1.46; 95% CI: 0.97, 2.20). At 2.5 years, those in both the second tertile of IL-6 (OR = 2.21; 95% CI: 1.44, 3.42) and the third tertile (OR = 2.03; 95% CI: 1.30, 3.19) were at increased risk of cognitive decline even after adjusting for all confounders. At 7 years of follow-up, only those in the highest IL-6 tertile were significantly more likely to exhibit declines in cognition (OR = 1.90; 95% CI: 1.14, 3.18) after adjustment for all confounders.

CONCLUSIONS

The results suggest a relationship between elevated baseline plasma IL-6 and risk for subsequent decline in cognitive function. These findings are consistent with the hypothesized relationship between brain inflammation, as measured here by elevated plasma IL-6, and neuropathologic disorders.

Measuring higher level physical function in well-functioning older adults: expanding familiar approaches in the Health ABC study

BACKGROUND

To evaluate development and progression of functional limitation and retain comparability with established approaches, we raised the measurement ceiling of commonly used self-report and performance-based measures of function. This study evaluated the utility and concurrent validity of these expanded measures.

METHODS

The study population consisted of 3075 black and white men and women aged 70 to 79 years, with no reported mobility limitations or disability, participating in the Health, Aging, and Body Composition, or Health ABC study. Self-report measures were expanded by ascertaining ease of performance and including more demanding levels of some tasks. A single foot stand and narrow walk supplemented an established performance battery. For walking endurance, we developed the Long Distance Corridor Walk (LDCW), which includes distance covered in 2 minutes and the time to walk 400 m.

RESULTS

The expanded self-report items identified one half of the men and one third of the women as exceptionally well functioning and 10% to 13% of men and 21% to 36% of women with lower capacity. The supplemented and rescored performance battery discriminated function over the full range. The LDCW further differentiated walking capacity at the high end and also identified a subgroup with limitations. The self-report and performance measures were significantly, but weakly, correlated (0.13-0.35) and were independent predictors of walking endurance.

CONCLUSIONS

Well-functioning persons in their 70s exhibit a broad range of functional capacity readily ascertained by expanded self-report and performance tests. Significant associations among these measures support their concurrent validity, but generally weak correlations indicate they tap different, but important, dimensions of physical function.

Social support, self-esteem and depression

A prospective study of 400 largely working-class women with children living at home has used measures of self-esteem and 'social support' to predict the risk of depression in the following year once a stressor had occurred. Actual support received at the time of any crisis in the follow-up year was also measured. Self-esteem was correlated quite highly with some of the measures of support. A core tie was defined as a husband, lover or someone named as very close at first contact. Negative evaluation of self (i.e. low self-esteem), and various indices of lack of support from a core tie at the first interview, were associated with a greatly increased risk of subsequent depression once a stressor occurred. Lack of support from a core tie at the time of the crisis was particularly highly associated with an increased risk. There was also a high risk among those who were 'let down' - that is, for those who did not receive the support which they might have expected in terms of the first interview material. It is concluded that it is essential for prospective enquiries to take account of the actual mobilization of support in the follow-up period.

The association of plasma IL-6 levels with functional disability in community-dwelling elderly

BACKGROUND

IL-6 is a multifunctional cytokine that has been shown to increase with age.

METHODS

Plasma IL-6 was measured by ELISA in 1,727 community-dwelling elderly subjects whose blood was drawn during the third in-person survey of the Duke Established Populations for Epidemiologic Studies of the Elderly (EPESE). Demographics, functional status (disability), and disease states were determined. Correlations of these factors with IL-6 were analyzed with Spearman's Rho while differences between groups were assessed by Wilcoxon test.

RESULTS

IL-6 levels were higher with age (p = .0001) even in this older population (> 70 years). There was a positive correlation between IL-6 and functional disability for each of the functional status measures (p = .0001), as well as a correlation between self-rated health and IL-6. Significantly higher median levels of IL-6 were found in subjects reporting prevalent cancer, heart attack, and high blood pressure, but not diabetes or arthritis. The association between age and functional status with high IL-6 remained when all other variables were controlled, in multivariable analysis.

CONCLUSIONS

This association between increased plasma IL-6 levels and functional status suggests that dysregulation of IL-6 may be related to the functional disability seen with aging, and that IL-6 may be useful as a component of an overall marker of health.

Intramuscular ketamine for pediatric sedation in the emergency department: safety profile in 1,022 cases

STUDY OBJECTIVE

To determine the safety of intramuscular ketamine when administered by emergency physicians for pediatric procedures in accordance with a defined protocol.

METHODS

We assembled a consecutive case series of children aged 15 years or younger who were given ketamine in the emergency departments of a university medical center and an affiliated county hospital over a 9-year period. A protocol for ketamine use (4 mg/kg, intramuscularly) was followed. Treating physicians were instructed to complete data forms recording complications and adequacy of sedation concurrent with patient care. Subsequent chart review was used to determine indications, adjunctive drugs, time to discharge, and adverse reactions for all patients.

RESULTS

Intramuscular ketamine was administered 1,022 times, mainly for laceration repair and fracture reduction. Physicians completed data forms for 431 of treated children (42%). Transient airway complications occurred in 1.4%: airway malalignment (n = 7), laryngospasm (n = 4), apnea (n = 2), and respiratory depression (n = 1). All were quickly identified and treated without intubation or sequelae. Emesis occurred in 6.7%, without evidence of aspiration. Mild recovery agitation occurred in 17.6%, moderate to severe agitation in 1.6%. No child required hospitalization for complications caused by ketamine. Ketamine produced acceptable sedation in 98% of patients. The median time from injection to emergency department discharge was 110 minutes for children given a single dose of ketamine.

CONCLUSION

Intramuscular ketamine may be administered safely by emergency physicians to facilitate pediatric procedures in accordance with a defined protocol and with appropriate monitoring. Ketamine is highly effective, has a wide margin of safety, does not require intravenous access, and uniquely preserves protective airway reflexes.

Longitudinal study of physical ability in the oldest-old

Based on 1984 data from the Longitudinal Study on Aging, one-third of White persons aged 80 or older living in the community (N = 1,791) were defined as having no difficulty in walking 1/4 of a mile, in lifting 10 pounds, in climbing 10 steps without resting, or in stooping, crouching or kneeling. Physical ability was associated with lower risk of death over two years mean follow-up; Relative odds (RO) = .4 (95 percent confidence interval = .4, .6) and in survivors, lower utilization of hospitals RO = .4 (CI = .3, .7), physicians RO = .6 (CI = .5, .8) and nursing homes RO = .3 (CI = .2, .5) compared with those having difficulty on any of the four functional measures included in the definition of physical ability. Fifty percent of the women and 42 percent of the men physically able at the time of the baseline survey in 1984 remained physically able at follow-up. Continued physical ability in this group was associated with never having had cardiovascular disease RO = 2.1, (CI = 1.2, 3.7), never having had arthritic complaints RO = 1.9 (CI = 1.2, 2.7), a body mass index less than the 75th percentile RO = 1.8 (CI = 1.2, 2.9), younger age (for each decade of age, RO = 2.0 (CI = 1.1, 3.6), and higher level of education (greater than 13 years versus 0-6 years) RO = 2.4 (CI = 1.2, 4.7). These correlates include factors amenable to preventive measures and highlight the need to consider the heterogeneity of the oldest-old in formulating programs aimed at prevention and postponement of disability.

Depression and loss

Recent losses occurring in the two years before onset of depression in women are distinguished from past losses occurring at any time before this. Of past losses only loss of mother before II is associated with greater risk of depression--both among women treated by psychiatrists and among women found to be suffering from depression in a random sample of 458 women living in London. Past loss of a father or sibling before 17 (or a mother between II and 17), or a child or husband, is not associated with a greater chance of developing depression. However, among patients all types of past loss by death are associated with psychotic-like depressive symptoms (and their severity) and other types of past loss with neurotic-type depressive symptoms (and their severity). It is argued that these associations probably reflect direct causal links, and a sociopsychological theory to explain them is discussed.

Number of pregnancies and the subsequent risk of cardiovascular disease

BACKGROUND

Whether increasing parity or gravidity is a risk factor for coronary heart disease has been debated, but the question remains unresolved.

METHODS

We tested the association between the number of pregnancies and a variety of cardiovascular end points in two groups of women who had completed childbearing. One group comprised 2357 women who were followed for 28 years through the Framingham Heart Study, and the other 2533 women followed for at least 12 years through the first National Health and Nutrition Examination Survey National Epidemiologic Follow-up Study (NHEFS).

RESULTS

The rates of coronary heart disease were higher among multigravid women than among women who had never been pregnant, in both the Framingham Heart Study and the NHEFS, but in both studies, the higher rates were statistically significant only in women with six or more pregnancies. For the women in the Framingham Study, the rate ratio adjusted for age and educational level in the group with six or more pregnancies (as compared with women who had never been pregnant) was 1.6 (95 percent confidence interval, 1.1 to 2.2). For the women in the NHEFS, the same adjusted rate ratio was 1.5 (95 percent confidence interval, 1.1 to 1.9). Adjustments for other known cardiovascular risk factors, including weight, did not markedly alter this risk. The rate of total cardiovascular disease was also significantly higher among multigravid women in the Framingham Study than in the women who had never been pregnant.

CONCLUSIONS

In two prospective American studies, having six or more pregnancies was associated with a small but consistent increase in the risk of coronary heart disease and cardiovascular disease. Whether gravidity itself or some other unmeasured factor accounts for the increase in risk that we observed requires further investigation.

Association of interleukin-6 and other biologic variables with depression in older people living in the community

OBJECTIVES

The prevalence of depression increases with age, as does the prevalence of higher levels of the cytokine interleukin-6 (IL-6). This analysis was performed to determine the association between increased levels of this cytokine and depression in a population-based sample.

DESIGN

Cross-sectional cohort study.

SETTING

Rural and urban counties in North Carolina.

PARTICIPANTS

Community-dwelling older people.

MEASUREMENTS

The association between IL-6 and other biologic variables with self-report depression was examined in 1686 persons aged 70 years and older in the third in-person survey wave (1991) of the Duke Established Population for Epidemiologic Studies of the Elderly (EPESE). Bivariate associations were established by the Spearman correlation, adjusted for age. A stepwise linear logistic regression model was used to derive a final model to assess multivariable effects on CES-D scores.

RESULTS

Depression was correlated with IL-6 (P = .011), D-Dimer (P = .017), alpha-1-globulin (P = .023), alpha-2-globulin (P = .002), and beta globulin (P = .012). After controlling for age, race, and gender, IL-6 levels remained the only biologic variable significantly associated with depression (P = .035).

CONCLUSION

These data suggest that the inflammatory marker, IL-6, is associated with depression in older people in this cross-sectional study. These results are compatible with the hypothesis of cytokine (IL-6) stimulation in geriatric depression as part of an overall immunoendocrine dysregulation.

Loss of parent in childhood and adult psychiatric disorder: the role of lack of adequate parental care

The inconclusiveness of the literature on the role of loss of parent in influencing psychiatric disorder in adulthood is well known. A number of reasons involving sampling, location and other methodological features, are given to account for these contradictory findings. A study specially designed to cope with these features is then described and basic results are reported. These indicate that, in a sample of women aged 18-65, loss of mother before the age of 17, either by death or by separation of one year or more, was associated with clinical depression in the year of interview. Loss of father by death was in no way associated with current depression, but separation from father showed a trend which, however, did not reach statistical significance. Control for other possible confounding factors did not change this patterning of results; these were further supported when psychiatric episodes earlier in adulthood were examined. Examination of the caregiving arrangements in childhood suggests that it is 'lack of care', defined in terms of neglect rather than simply hostile parental behaviour, which accounts for the raised rate of depression. Such 'lack of care' is more frequent after loss of mother than after loss of father.

Measuring fitness in healthy older adults: the Health ABC Long Distance Corridor Walk

OBJECTIVES

The Health ABC Long Distance Corridor Walk (LDCW) was designed to extend the testing range of self-paced walking tests of fitness for older adults by including a warm-up and timing performance over 400 meters. This study compares performance on the LDCW and 6-minute walk to determine whether the LDCW encourages greater participant effort.

DESIGN

Subjects were administered the LDCW and 6-minute walk during a single visit. Test order alternated between subjects, and a 15-minute rest was given between tests.

SETTING

The Baltimore Veterans Affairs Medical Center.

PARTICIPANTS

Twenty volunteers age 70 to 78.

MEASUREMENTS

The LDCW, consisting of a 2-minute warm-up walk followed by a 400-meter walk and a 6-minute walk test were administered using a 20-meter long course in an unobstructed hallway. Heart rate (HR) and blood pressure (BP) were recorded at rest and before and after all walks.

RESULTS

All 20 subjects walked a faster pace over 400 meters than for 6 minutes, in which the mean distance covered was 402 meters. From paired t-tests, walking speed was faster (mean difference = 0.23 m/sec; P < .001), and ending HR (mean difference = 7.6 bpm; P < .001) and systolic BP (mean difference = 8.3 mmHg; P = .024) were greater for the 400-meter walk than for the 6-minute walk. Results were independent of test order and subject fitness level.

CONCLUSIONS

Providing a warm-up walk and using a target distance instead of time encouraged subjects to work closer to their maximum capacity. This low-cost alternative to treadmill testing can be used in research and clinical settings to assess fitness and help identify early functional decline in older adults.

Learning disability and epilepsy in an epidemiological sample of individuals with tuberous sclerosis complex

BACKGROUND

Intellectual impairments are a recognized feature of tuberous sclerosis complex (TSC), but the frequency and degree of intellectual impairments has not been systematically studied in large epidemiological samples using standardized measures. As such, the form of the IQ distribution (uni- or bi-modal) has not been established and the relationship between IQ and other features (e.g. epilepsy history) is poorly delineated. To address these shortcomings, we assessed the intellectual abilities of a large epidemiological sample of individuals with TSC, drawn from the 'Wessex' area of SW England and compared them with the abilities of their unaffected siblings.

METHOD

Standardized tests were used to estimate the abilities of 108 (56 males, 52 females, median age = 25, range = 4-75) individuals with TSC and 29 unaffected siblings (14 males, 15 females, median age = 18, range = 6-55). Seizure history was obtained from informants and medical records.

RESULTS

Estimated IQ was bi-modally distributed: 55.5% had an IQ in the normal range; 14% had mild to severe impairments: and 30.5% had profound disability (IQ < 21). Forty-four per cent of the individuals with TSC had an IQ < 70. In the subset of normally intelligent individuals with TSC, IQ was normally distributed with a mean of 93.6. This mean was significantly lower than the mean IQ of unaffected siblings (IQ = 105.6). All individuals with learning disability had a history of seizures that usually commenced before 12 months of age and that often presented as infantile spasms. Multivariate analyses indicated that a history of seizures as well as a history of infantile spasms was predictive of the degree of intellectual impairment.

CONCLUSIONS

Intellectual abilities were bi-modally distributed in a representative sample of individuals with TSC. The likelihood of impairment was associated with a history of seizures, particularly infantile spasms. The genetic and brain basis of these findings requires further investigation.

Social origins of depression: a reply

Many of the criticisms of our work made by Tennant & Bebbington in the current edition of this journal touch on issues which have already been discussed in our recent book Social Origins of Depression. We do not think that any of their points pose significant threats to our aetiological model of depression. We welcome this opportunity to clarify their questions about our data, and to use their re-analysis of our material as a basis for a wider discussion of certain general aspects of the statistical analysis and interpretation of data and the pitfalls which await the unwary.

Self-reported causes of physical disability in older people: the Cardiovascular Health Study. CHS Collaborative Research Group

OBJECTIVE

To determine the major conditions and symptoms reported to cause difficulty in 17 physical tasks of daily life and the criterion validity of self-report of diseases given as the causes of the difficulty in functioning, in community-dwelling older people.

DESIGN

Cross sectional analyses of data obtained in an observational cohort study.

SETTING

Research clinics in four US communities: Winston-Salem, NC, Hagerstown, MD, Pittsburgh, PA, and Sacramento, CA.

PARTICIPANTS

5201 community-dwelling people > or = 65 years old.

RESULTS

Arthritis and other musculoskeletal diseases were given as the primary causes of difficulty in performing physical tasks by 49.0% of the participants reporting difficulty in any task, followed by heart disease (13.7%), injury (12.0%), old age (11.7%), lung disease (6.0%), and stroke (2.9%). The self-reports of diseases that caused disability varied by task. Whereas arthritis was given as a cause of difficulty in most of the 17 different tasks, heart and lung disease were more likely to be reported as causing difficulty with activities requiring high aerobic work capacity such as walking one-half mile or doing heavy housework. Stroke was more likely to be reported as causing difficulty with use of the upper extremities and in performing basic activities of daily living. There was a high degree of consistency (91%) between the diseases and symptoms reported to cause disabilities. The percentage of people who reported a disease as the cause of their difficulty performing a task and had independent confirmation of the diagnosis was 85% in men and 71% in women, and varied according to type of disease and the individual's cognitive status and health status.

CONCLUSION

These data suggest that age-related chronic diseases are important causes of disability in older people but that the type of disability is dependent on the underlying disease that causes the disability. Also, self-report of the cause of disability appears to be generally accurate but is influenced by gender, health status, and type of disease.

Inflammatory markers are associated with ventilatory limitation and muscle dysfunction in obstructive lung disease in well functioning elderly subjects

BACKGROUND

Inflammatory markers are increased in chronic obstructive pulmonary disease (COPD) and are hypothesised to play an important part in muscle dysfunction and exercise intolerance.

METHODS

The Health Aging and Body Composition (Health ABC) study is a prospective observational cohort of well functioning individuals aged 70-79 years. A cross sectional analysis of the baseline data was conducted to examine the association between inflammatory markers and ventilatory limitation, muscle strength, and exercise capacity. These associations were compared in participants with and without obstructive lung disease (OLD).

RESULTS

Of the 3075 participants enrolled in the Health ABC cohort, OLD was identified by spirometric testing in 268 participants and 2005 participants had normal spirometric results. Of the participants with OLD, 35%, 38%, and 27% participants had mild, moderate, and severe OLD, respectively. Participants with OLD had lower quadriceps strength (102.5 Nm v 108.9 Nm, p = 0.02), lower maximum inspiratory pressure (64.7 cm H(2)O v 74.2 cm H(2)O, p<0.0001), higher systemic interleukin (IL)-6 levels (2.6 pg/ml v 2.2 pg/ml, p<0.0001), and higher C-reactive protein (CRP) levels (3.5 mg/l v 2.5 mg/l, p<0.0001) than those with normal spirometry. In participants with OLD and those with normal spirometry, forced expiratory volume in 1 second (FEV(1)) was associated with IL-6 (adjusted regression coefficients (beta) = -5.3 (95% CI -9.1 to-1.5) and -3.1 (95% CI -4.3 to -1.9), respectively). IL-6 and TNF were also associated with quadriceps strength among participants with OLD and those with normal spirometry (beta = -6.4 (95% CI -12.8 to -0.03) and -3.4 (95% CI -5.4 to -1.3), respectively, for IL-6 and beta = -10.1 (95% CI -18.7 to -1.5) and -3.8 (95% CI -7 to -0.6), respectively, for TNF). IL-6, quadriceps strength, and maximum inspiratory pressures were independent predictors of reduced exercise capacity in both groups.

CONCLUSIONS

In well functioning elderly subjects with or without OLD, IL-6 is associated with reduced FEV(1), quadriceps strength, and exercise capacity.

Clarifying the direct relation between total cholesterol levels and death from coronary heart disease in older persons

BACKGROUND

The importance of total cholesterol level as a risk factor for coronary heart disease in older adults is controversial.

OBJECTIVE

To determine whether findings showing that total cholesterol level is not an important risk factor for coronary heart disease in older adults are the result of inadequate adjustment for co-occurring diseases and frailty.

DESIGN

Multicenter, longitudinal study with 5-year follow-up for death.

PARTICIPANTS

4066 men and women from East Boston, Massachusetts; Iowa and Washington counties, Iowa; and New Haven, Connecticut.

MEASUREMENTS

In 1988, participants were interviewed about their health status and had blood samples taken. Mortality follow-up was through 1992.

RESULTS

In analyses that included all fatal coronary heart disease events (252 deaths) and did not adjust for risk factors for coronary heart disease and measures of frailty, persons with the lowest total cholesterol levels (< or = 4.15 mmol/L [< or = 160 mg/dL]) had the highest rate of death from coronary heart disease, whereas those with elevated total cholesterol levels (> or = 6.20 mmol/L [> or = 240 mg/dL]) seemed to have a lower risk for death from coronary heart disease (P for trend = 0.04). After adjustment for established risk factors for coronary heart disease and markers of poor health (including chronic conditions, low serum iron and albumin levels) and exclusion of 44 deaths from coronary heart disease that occurred within the first year, elevated total cholesterol levels predicted increased risk for death from coronary heart disease, and the risk for death from coronary heart disease decreased as cholesterol levels decreased (P for trend = 0.005).

CONCLUSIONS

Elevated total cholesterol level is a risk factor for death from coronary heart disease in older adults, and the apparent adverse effects associated with low cholesterol levels are secondary to comorbidity and frailty. This suggests that excluding older persons from cholesterol screening is inappropriate, but interpretation of screening results in older persons requires clinical judgment. Results from controlled clinical trials are needed to clarify this issue.

The relation of infantile spasms, tubers, and intelligence in tuberous sclerosis complex

BACKGROUND

The aetiology of the learning difficulty in tuberous sclerosis is debated. It may be related to the amount of tubers in the brain or caused by the infantile spasms that occur in early life.

AIMS

To examine the relative contributions to final intelligence (IQ) made by both cerebral tubers and infantile spasms.

METHODS

As part of an epidemiological study of tuberous sclerosis in the south of England, patients were recruited who were able to undergo magnetic resonance imaging (MRI) without the need for an anaesthetic. Epilepsy history was determined by interview and review of clinical records. IQ was assessed using either Wechsler intelligence scales or Raven's matrices.

RESULTS

A total of 41 patients consented to have an MRI scan. IQ scores were normally distributed about a mean of 91. Twenty six patients had a positive history of epilepsy, and 11 had suffered from infantile spasms. There was a significant relation between the number of tubers and IQ. Infantile spasm status partly confounded the relation between tubers and IQ, but did not render the relation statistically insignificant. The relation between infantile spasms and learning difficulty remained strong even when controlling for the number of tubers.

The burden and outcomes associated with dehydration among US elderly, 1991

OBJECTIVES

Dehydration has been underappreciated as a cause of hospitalization and increased hospital-associated mortality in older people. This study used national data to analyze the burden and outcomes following hospitalizations with dehydration in the elderly.

METHODS

Data from 1991 Medicare files were used to calculate rates of hospitalization with dehydration, to examine demographic characteristics and concomitant diagnoses associated with dehydration, and to analyze the contribution of dehydration to mortality.

RESULTS

In 1991, 6.7% (731,695) of Medicare hospitalizations had dehydration listed as one of the five reported diagnoses, a rate of 236.2/10,000 elderly Medicare beneficiaries. In 1991, Medicare reimbursed over $446 million for hospitalizations with dehydration as the principal diagnosis. Older people, men, and Blacks had elevated risks for hospitalization with dehydration. Acute infections, such as pneumonia and urinary tract infections, were frequent concomitant diagnoses. About 50% of elderly Medicare beneficiaries hospitalized with dehydration died within a year of admission.

CONCLUSIONS

Hospitalization of elderly people with dehydration is a serious and costly medical problem. Attention should be focused on understanding predisposing factors and devising strategies for prevention.