Search PubMed⌕ Search

Biomedical subjects

R S Paffenbarger

Publications and source records attributed to R S Paffenbarger.

At least 19 recordsLinked to original sources
PubMed1992

Change in body weight and longevity.

OBJECTIVE: To investigate the effect of body weight change on longevity. DESIGN: Cohort analytic study, following men from 1977 through 1988. SETTING: The study was conducted among Harvard University alumni with mean age of 58 years. PATIENTS: Alumni, free of cardiovascular disease and cancer, completed questionnaires on weight, height, cigarette habit, and physical activities in 1962 or 1966 and in 1977 (n = 11,703). We assessed weight change between questionnaires, based on self-reported weights. MAIN OUTCOME MEASURE: Mortality from all causes (n = 1441), coronary heart disease (n = 345), and cancer (n = 459), determined from death certificates. RESULTS: Lowest all-cause mortality was among alumni maintaining stable weight (+/- 1 kg). With this category as referent (relative risk = 1.00), relative risks of death associated with losing more than 5 kg, losing between 1 and 5 kg, (more than 1 kg and up to 5 kg) gaining between 1 and 5 kg (more than 1 kg and up to 5 kg), and gaining more than 5 kg were 1.57 (95% confidence interval, 1.34 to 1.84), 1.26 (1.10 to 1.46), 1.06 (0.90 to 1.24), and 1.36 (1.11 to 1.66), respectively. For coronary heart disease mortality, relative risks were 1.75 (1.26 to 2.43), 1.43 (1.05 to 1.93), 1.28 (0.91 to 1.80), and 2.01 (1.36 to 2.97), respectively. Weight change did not predict cancer mortality. Findings were not explained by cigarette habit, physical activity, or body mass index. We observed similar trends for follow-up between 1977 and 1982 and between 1983 and 1988. Those losing or gaining more weight also reported greater total lifetime weight loss, which may indicate weight cycling. CONCLUSIONS: Both body weight loss and weight gain are associated with significantly increased mortality from all causes and from coronary heart disease but not from cancer.

Analysis of Variance↗
PubMed1992

Quetelet's index and risk of colon cancer in college alumni.

BACKGROUND: While previous studies suggest that overweight, middle-aged men may face increased risk of colon cancer, it is unclear whether their weights as young adults influence this risk. It is also unknown whether their level of physical activity affects their risk of developing colon cancer. PURPOSE: To determine the relationship between being overweight in middle-age or young adulthood and colon cancer risk, we prospectively studied alumni of Harvard University. We also investigated whether being overweight influences risk differently for men with different levels of physical activity. METHODS: In 1962 or 1966 (1962/1966), alumni completed questionnaires on weight, height, other sociodemographic characteristics, and medical history. We obtained information on weight and height at college entry from university archives. Alumni (n = 17,595) were followed from 1962/1966 to 1988 for colon cancer occurrence, ascertained from follow-up questionnaires in 1977 and 1988 and death certificates. RESULTS: Between 1962/1966 and 1988, 302 cases of colon cancer were diagnosed. Colon cancer risk increased with higher levels of Quetelet's index (weight [kg]/height [m]2) in 1962/1966. Relative risk per unit increase, adjusted for age, physical activity, and parental history of cancer, was 1.08 (95% confidence interval [CI], 1.04-1.13). Quetelet's index at college entry did not predict risk as well (adjusted relative risk per unit increase, 1.05; 95% CI, 1.00-1.10). The heaviest fifth of alumni during both college time and in 1962/1966 had almost two and one-half times the risk of the lightest fifth of alumni (adjusted relative risk, 2.40; 95% CI, 1.40-4.13). When alumni were classified according to activity level in 1962/1966, higher levels of Quetelet's index were significantly associated with colon cancer risk only among those who were less active. CONCLUSIONS: Overweight during middle-age or young adulthood is associated with higher colon cancer risk; in overweight, physically active men, however, the risk of colon cancer may not be increased.

Adult↗
PubMed1992

Time trends in physical activity among college alumni, 1962-1988.

Little direct evidence exists in the epidemiologic literature to support the widely held belief that an individual's physical activity behavior varies over the years. To provide data, the authors prospectively studied patterns of physical activity among 6,092 Harvard College alumni (average age at the start of follow-up, 43 years) who responded to questionnaires in 1962 or 1966, 1977, and 1988, and who declared themselves free of cardiovascular disease and cancer throughout that period. The median energy expenditure increased between 1962 or 1966 and 1977, but stabilized between 1977 and 1988. However, rank correlation coefficients between estimates of energy expenditure in 1977 and 1988 ranged from 0.36 to 0.41 for the various age groups (compared with 0.81-0.84 for the Quetelet index, and 0.60-0.65 for the current number of cigarettes smoked per day), implying that physical activity at the individual level was not constant. For 4,238 alumni for whom data on collegiate sports participation were available, the rank correlation coefficients between collegiate activity and alumni activity 1-7 decades later were even lower, ranging from 0.05 to 0.17 (compared with 0.31-0.58 for the Quetelet index). Thus, physical activity assessed over a short time period in an individual may not be a valid proxy for activity over the long term. The characteristics that distinguished alumni who consistently expended less than 1,000 kcal/week (in climbing stairs, walking, and playing sports) in 1962 or 1966, 1977, and 1988 from those who consistently expended greater than 2,500 kcal/week were as follows: at baseline, older age, overweight, and cigarette smoking; and during college, not having been a varsity athlete and fewer hours playing sports.

Adult↗
PubMed1992

Physical activity and risk of prostatic cancer among college alumni.

Clinical observations and laboratory experiments have suggested a role for testosterone in the development of prostatic cancer. Since physical training may act to lower testosterone levels, men who are very active may have a reduced risk of this cancer. To test this hypothesis, the authors prospectively followed 17,719 Harvard alumni (aged 30-79 years) from 1965 or 1969 to 1977, and 1980 to 1988 for the occurrence of prostatic cancer (n = 419). Physical activity was assessed in either 1962 or 1966, and again in 1977, based on self-reported stair climbing, walking, and sports played. Alumni who expended greater than 4,000 kcal/week at both assessments were at reduced risk of developing prostatic cancer (age-adjusted rate ratio, 0.12; 95% confidence interval 0.02-0.89) compared with their inactive counterparts who expended less than 1,000 kcal/week at both assessments. These results should be interpreted cautiously, since only one case of prostatic cancer was identified among alumni highly active at both assessments, who contributed 4% of total person-years to the analysis. Among alumni aged 70 years and older, those who extended greater than 4,000 kcal/week at either assessment had about half the risk of those who expended less than 1,000 kcal/week at either assessment (age-adjusted rate ratio, 0.53; 95% confidence interval 0.29-0.95). The authors attribute these findings to the increased precision with which physical activity could be measured when combining two activity assessments. Alternatively, long-term maintenance of a high level of physical activity may be necessary for further reduction of risk. There was no evidence of a dose-response relation.

Adult↗
PubMed1992

The role of physical exercise in the occurrence of Parkinson's disease.

A case-control study of Parkinson's disease and physical exercise was conducted in a cohort of 50,002 men who attended Harvard College (Cambridge, Mass) or the University of Pennsylvania (Philadelphia) between 1916 and 1950 and were followed up in adulthood for morbidity and mortality data. Cases of Parkinson's disease were identified from responses to mailed questionnaires and death certificates through 1978. Four controls from the same population were selected for each case. The association between physical activity at the time of college and subsequent risk of Parkinson's disease was evaluated for 137 cases and 548 controls, whereas the data on physical activity in adulthood before the disease occurrence was available only for 94 of these cases. Having belonged to a varsity team or having done regular physical exercise in college was associated with a lower nonsignificant risk of Parkinson's disease. In adulthood, practice of moderate or heavy sports was linked to a reduced risk, although more precise analysis revealed that there was only a modest nonsignificant reduction in risk for subjects who do a moderate amount of physical exercise, but this negative association disappears at higher levels of physical expenditure. These results, which require further confirmation, are compatible with a slight protective effect of physical exercise on the risk of Parkinson's disease, although the lack of association cannot be refuted.

Adolescent↗
PubMed1992

How much physical activity is good for health?

Research studies over the past several decades confirm the health benefits of regular physical activity, a concept with foundations in antiquity. The effects of activity on certain individual health conditions, the precise dose of activity that is required for specific benefits, the role (if any) of intensity of effort, and the elucidation of biological pathways whereby activity contributes to health are topics for further research. Although details remain to be clarified, it is now clear that regular physical activity reduces the risk of morbidity and mortality from several chronic diseases and increases physical fitness, which leads to improved function. Table 3 outlines the relationship of activity to several diseases, a judgment on the strength of the evidence, and a rough determination of the amount of research extant. Results from clinical exercise studies and epidemiological investigations can be integrated into a consistent and coherent theory of healthful physical activity. However, some differences between these two research streams need to be reconciled. Exercise physiologists have generally recommended relatively intensive activity and a formal approach to exercise prescription. The epidemiological studies suggest a linear dose-response relationship, at least up to a point, between physical activity and health and functional effects. These data support public health recommendations directed toward the most sedentary and unfit stratum of the population and emphasize doing at least moderate physical activity. If this group of adults would accumulate 30 minutes of walking per day (or the equivalent energy expenditure in other activities), they would receive clinically significant health benefits. An important point is that it does not matter what type of physical activity is performed: Sports, planned exercise, household or yard work, or occupational tasks are all beneficial. The key factor is total energy expenditure; if that is constant, improvements in fitness and health will be comparable. There are probably 40 million adults in the US whose sedentary habits place them at considerably increased risk of morbidity and mortality from several diseases. These same individuals also are more likely to have functional limitations, especially as they move into the later years of life. The sizable independent relative risk for impaired health in sedentary persons, and the large number at risk, leads to a substantial public health burden. This problem deserves continued and increased attention by physicians and other health professionals, scientists, and the public health establishment.

Biological Evolution↗
PubMed1991

Physical activity and risk of developing colorectal cancer among college alumni.

The assessment of physical activity at a single time to evaluate its association with cancer may be limited, since such a measure may not adequately reflect activity over the long term. To overcome this limitation, we studied 17,148 Harvard alumni aged 30-79 years who were followed prospectively for the occurrence of colon cancer (n = 225) and rectal cancer (n = 44) from 1965 through 1988. Physical activity, based on self-reported stair climbing, walking, and sports play, was assessed in either 1962 or 1966 (1962/1966) and again in 1977. The increased activity evaluated using either assessment (1962/1966 or 1977) taken alone was not associated with risk of colon cancer. However, alumni who were highly active (energy expenditure of greater than 2500 kilocalories/wk) at both assessments had half the risk of developing colon cancer relative to those who were inactive (less than 1000 kilocalories/wk) at both assessments (age-adjusted rate ratio = 0.50; 90% confidence interval = 0.27-0.93), whereas those who were moderately active (1000-2500 kilocalories/wk) at both assessments had an age-adjusted rate ratio of 0.52 (90% confidence interval = 0.28-0.94). We conclude that either consistently higher levels of activity are necessary to protect against colon cancer or combining two assessments increased the precision of physical activity measurement. We found no evidence that increased physical activity protected against rectal cancer.

Adult↗
PubMed1991

Physical activity and reduced occurrence of non-insulin-dependent diabetes mellitus.

BACKGROUND: Physical activity is recommended by physicians to patients with non-insulin-dependent diabetes mellitus (NIDDM), because it increases sensitivity to insulin. Whether physical activity is effective in preventing this disease is not known. METHODS: We used questionnaires to examine patterns of physical activity and other personal characteristics in relation to the subsequent development of NIDDM in 5990 male alumni of the University of Pennsylvania. The disease developed in a total of 202 men during 98,524 man-years of follow-up from 1962 to 1976. RESULTS: Leisure-time physical activity, expressed in kilocalories expended per week in walking, stair climbing, and sports, was inversely related to the development of NIDDM: The incidence rates declined as energy expenditure increased from less than 500 kcal to 3500 kcal. For each 500-kcal increment in energy expenditure, the age-adjusted risk of NIDDM was reduced by 6 percent (relative risk, 0.94; 95 percent confidence interval, 0.90 to 0.98). This association remained the same when the data were adjusted for obesity, hypertension, and a parental history of diabetes. The association was weaker when we considered weight gain between the time of college attendance and 1962 (relative risk, 0.95; 95 percent confidence interval, 0.90 to 1.00). The protective effect of physical activity was strongest in persons at highest risk for NIDDM, defined as those with a high body-mass index, a history of hypertension, or a parental history of diabetes. These factors, in addition to weight gain since college, were also independent predictors of the disease. CONCLUSIONS: Increased physical activity is effective in preventing NIDDM, and the protective benefit is especially pronounced in persons at the highest risk for the disease.

Adult↗
PubMed1991

Physical activity and hypertension: an epidemiological view.

We examined patterns of physical activity and other characteristics that might deter hypertension or delay all-cause mortality among university alumni, 1962-1985. Collegiate sports play did not alter hypertension incidence, nor did contemporary walking, stair-climbing, or light sports play among 5463 University of Pennsylvania alumni, 739 of whom developed hypertension. But vigorous sports play reduced hypertension incidence; and overweight, gain in weight, history of parental hypertension, or any combination of these, increased it. Among 819 hypertensive Pennsylvania alumni (138 died during follow-up), vigorous sports play had minimal influence on mortality; but freedom from overweight and cigarette smoking deferred death. Among 16,936 Harvard College alumni, of whom 2614 died during follow-up, lack of vigorous sports play, or presence of hypertension, cigarette smoking, and overweight increased risk of premature mortality, heightened by any combination of these adverse characteristics. Overall, we found an inverse relationship between vigorous sports participation and hypertension risk but a direct relationship between risk and weight-for-height, weight gain, or parental hypertension. With regard to all-cause mortality, cigarette smoking and hypertension were most hazardous for the individual; smoking and lack of vigorous recreational play were most hazardous for the alumnus population as a whole.

Adult↗
PubMed1990

Smoking and Parkinson's disease.

A case-control analysis of Parkinson's disease and smoking habits was conducted in a cohort of 50,002 men who attended Harvard College (Cambridge, MA) or the University of Pennsylvania (Philadelphia, PA) between 1916 and 1950 and were followed in adulthood for morbidity and mortality data. Ninety-six cases of Parkinson's disease were identified from responses to a mailed questionnaire, addressed in 1976 to the University of Pennsylvania alumni and in 1977-1978 to the Harvard alumni. Four controls from the same population were selected for each case. Even though no statistically significant association was found, the results support a negative association between cigarette smoking and Parkinson's disease.

Case-Control Studies↗
PubMed1989

Physical fitness and all-cause mortality. A prospective study of healthy men and women.

We studied physical fitness and risk of all-cause and cause-specific mortality in 10,224 men and 3120 women who were given a preventive medical examination. Physical fitness was measured by a maximal treadmill exercise test. Average follow-up was slightly more than 8 years, for a total of 110,482 person-years of observation. There were 240 deaths in men and 43 deaths in women. Age-adjusted all-cause mortality rates declined across physical fitness quintiles from 64.0 per 10,000 person-years in the least-fit men to 18.6 per 10,000 person-years in the most-fit men (slope, -4.5). Corresponding values for women were 39.5 per 10,000 person-years to 8.5 per 10,000 person-years (slope, -5.5). These trends remained after statistical adjustment for age, smoking habit, cholesterol level, systolic blood pressure, fasting blood glucose level, parental history of coronary heart disease, and follow-up interval. Lower mortality rates in higher fitness categories also were seen for cardiovascular disease and cancer of combined sites. Attributable risk estimates for all-cause mortality indicated that low physical fitness was an important risk factor in both men and women. Higher levels of physical fitness appear to delay all-cause mortality primarily due to lowered rates of cardiovascular disease and cancer.

Adult↗
PubMed1989

Epithelial ovarian cancer and the ability to conceive.

Relationships between ovarian cancer and ability to conceive were explored in a case-control study of 188 women with histologically confirmed epithelial ovarian cancer and 539 control women in the San Francisco Bay Area. Control women consisted of two groups: those hospitalized without cancer, matched to cases by age, race, and hospital of diagnosis (n = 280); and those selected from the general population by random digital dialing, matched to cases by age, race, and telephone prefix (n = 259). Ovarian cancer risk among nulliparous (but not parous) women was positively associated with a history of unsuccessful attempts to conceive, of physician-diagnosed infertility, and of doubts about ability to conceive. Among all women, risk increased with increasing years of unprotected intercourse (P value for trend = 0.02). Risk among women having 10 or more yr of unprotected intercourse was 1.8 relative to that among women having less than 2 such yr (P = 0.01). This association was independent of parity, oral contraceptive use, and estimated years of ovulation, each associated with ovarian cancer. Further, duration of unprotected intercourse combined multiplicatively with each of these latter characteristics in increasing ovarian cancer risk. For example, while cancer risk exhibited a 2-fold range from lowest to highest years of unprotected intercourse and a 4-fold range from lowest to highest years of ovulation, risk among women in the highest joint category of these characteristics was 8 times that of women in the lowest category. We believe that some abnormality of ovulation that reduces the likelihood of conception plays a role in epithelial ovarian cancer.

Adult↗
PubMed1989

An overview of randomized trials of rehabilitation with exercise after myocardial infarction.

Of 22 randomized trials of rehabilitation with exercise after myocardial infarction (MI), one trial had results that achieved conventional statistical significance. To determine whether or not these studies, in the aggregate, show a significant benefit of rehabilitation after myocardial infarction, we performed an overview of all randomized trials, involving 4,554 patients; we evaluated total and cardiovascular mortality, sudden death, and fatal and nonfatal reinfarction. For each endpoint, we calculated an odds ratio (OR) and 95% confidence interval (95% CI) for the trials combined. After an average of 3 years of follow-up, the ORs were significantly lower in the rehabilitation than in the comparison group: specifically, total mortality (OR = 0.80 [0.66, 0.96]), cardiovascular mortality (OR = 0.78 [0.63, 0.96]), and fatal reinfarction (OR = 0.75 [0.59, 0.95]). The OR for sudden death was significantly lower in the rehabilitation than in the comparison group at 1 year (OR = 0.63 [0.41, 0.97]). The data were compatible with a benefit at 2 (OR = 0.76 [0.54, 1.06]) and 3 years (OR = 0.92 [0.69, 1.23]), but these findings were not statistically significant. For nonfatal reinfarction, there were no significant differences between the two groups after 1 (OR = 1.09 [0.76, 1.57]), 2 (OR = 1.10 [0.82, 1.47]), or 3 years (OR = 1.09 [0.88, 1.34]) of follow-up. The observed 20% reduction in overall mortality reflects a decreased risk of cardiovascular mortality and fatal reinfarction throughout at least 3 years and a reduction in sudden death during the 1st year after infarction and possibly for 2-3 years. With respect to the independent effects of the physical exercise component of cardiac rehabilitation, the relatively small number of "exercise only" trials, combined with the possibility that they may have had a formal or informal nonexercise component precludes the possibility of reaching any definitive conclusion. To do so would require a randomized trial of sufficient size to distinguish between no effect and the most plausible effect based on the results of this overview.

Clinical Trials as Topic↗