The influence of physical activity on the incidence of site-specific cancers in college alumni.
Explore the source record for details and available documents.
Breast Neoplasms↗
Biomedical subjects
R S Paffenbarger
Publications and source records attributed to R S Paffenbarger.
Physical activity, physical fitness, and sudden cardiac death.
Explore the source record for details and available documents.
Cardiomyopathy, Hypertrophic↗
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↗
Determinants of physical activity and interventions in adults.
Explore the source record for details and available documents.
Adult↗
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↗
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↗
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↗
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↗
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↗
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↗
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↗
Body size, reproductive factors, and breast cancer survival.
Mortality rates among 838 white female breast cancer patients were examined for relationships to personal characteristics assessed at time of diagnosis. These included weight and body mass index, oral contraceptive use, and prior menstrual and reproductive events. Multivariate analyses were used to determine the importance of these characteristics in predicting death rates specific for age and extent of disease at time of diagnosis. Weight was associated with poor prognosis among premenopausal patients, but not among postmenopausal patients. Premenopausal women weighing more than 140 lbs at diagnosis had death rates 1.7 times those of lighter women (P = 0.04). This effect was not explained by differences in the distribution of disease stage between the two groups. Body mass index was positively associated with mortality in both premenopausal and postmenopausal patients. In the entire group, the death rate ratio was 1.4 (P = 0.02) for obese (body mass index greater than 30.4 X 10(-3) lbs/in.2) vs lean women. Among premenopausal patients, parous women had higher mortality rates than nulliparous women (death rate ratio = 2.0, P = 0.06). Although the data were sparse, death rates were higher for women having a full-term pregnancy within 2 years of diagnosis than for premenopausal women with earlier pregnancies. Oral contraceptive use, age at menarche, age at first full term birth, and age at menopause were unrelated to mortality.
Adult↗
A mail survey of physical activity habits as related to measured physical fitness.
The associations of self-reported measures of physical activity from a mail survey with an objective measure of physical fitness were investigated. Respondents to a health status survey (n = 12,225), conducted in 1982 by the Institute for Aerobics Research in Dallas, TX, formed the population. From this group, males who also had a clinical examination within 60 days of the return of their questionnaire served as subjects. The study subjects (n = 375, mean age = 47.1 years) completed a maximal physical fitness assessment using a modified Balke protocol. The questionnaire included a section of inquiries concerning leisure time physical activity participation in which subjects were asked to quantitatively recall exercise participation for varying periods of time. Reported exercise participation values were converted to estimates of energy expenditure and combined into overall indices of physical activity participation. Multiple regression analyses were used to determine the individual contributions of the physical activity indices in predicting maximal treadmill performance (physical fitness). Significant predictors of physical fitness were age (beta = -0.34), an index of running, walking, and jogging participation (beta = 0.31), and the response to a question on frequency of sweating (beta = 0.35). The multiple correlation coefficient for these variables in predicting physical fitness was 0.65. These results indicate that exercise behavior can be accurately estimated in large populations by using simple questions in a mail survey.
Adult↗
Combined effect of childbearing, menstrual events, and body size on age-specific breast cancer risk.
Pike et al. (Nature 1983;303:767-70) and Moolgavkar et al. (JNCI 1980;65:59-69) proposed quantitative theories for the effect on age-specific breast cancer risk of ages at menarche, first childbirth, and menopause. Here the incidence rate functions predicted by these theories are fit to data for 1,884 women of all ages with breast cancer and 3,432 matched controls admitted to San Francisco Bay area hospitals in 1970-1977. A third function describing age-specific breast cancer risk based on the timing of childbearing and menstrual events is presented, and its fit to the data is compared with that of the functions of Pike et al. and Moolgavkar et al. None of the three fully accounted for the protective effects of early age at first childbirth in premenopausal women or of early age at menopause in parous postmenopausal women. To account for the effects of total parity and body mass (Quetelet) index on risk of breast cancer occurrence, the authors developed a fourth incidence rate function by extending the third. Goodness of fit to the data of the fourth function is demonstrated. Age-specific relative risks of breast cancer according to childbearing, menstrual events, and body size are estimated from the fourth function. The main qualitative findings are that 1) the protective effects of late menarche and of early first full-term pregnancy are greater in premenopausal than in postmenopausal women; 2) first full-term pregnancy initially boosts the level of risk, but incidence rates increase with age more slowly thereafter; 3) among the parous, multiparity is protective both in premenopausal and postmenopausal women, regardless of age at first full-term pregnancy; 4) both nulliparous and lean women are more protected by early menopause than are parous and overweight women; 5) increased body mass index is protective before, but detrimental after, menopause; and 6) postmenopausal incidence rates increase with age more rapidly among overweight than among lean women.
Adolescent↗
Personal and environmental characteristics related to epithelial ovarian cancer. I. Reproductive and menstrual events and oral contraceptive use.
In two case-control studies conducted in the six-county San Francisco Bay Area, 111 women diagnosed with epithelial ovarian carcinoma in 1974-1977 and 188 women diagnosed in 1983-1985 were interviewed concerning their menstrual, sexual, and reproductive histories. For comparison, interviews were conducted with 752 control women admitted to the same hospitals within six months of the cases; for cases diagnosed in the later period, interviews were also conducted with an additional 259 population-based controls selected by random digit dialing. Controls were matched to cases by age and race. Qualitative and quantitative findings were similar for the two studies. In the combined data, cases were more likely than their matched controls to have been nulliparous, to have undergone menarche at an early age, and to have refrained from using oral contraceptives. Menopause occurred slightly later for cases than for controls, but the differences were not statistically significant. Neither age at first term pregnancy (20 or more weeks gestation) nor number of term pregnancies was predictive of ovarian cancer risk. The protection afforded by oral contraceptive use was independent of parity, and it increased with increasing duration of use. There were no trends in risk with time since last oral contraceptive use or with time since first use, after adjustment for duration of use. These observations suggest that oral contraceptive use decreases risk for ovarian cancer, rather than merely indicates fertility, which may itself decrease risk of developing the disease. The authors combined reproductive characteristics and oral contraceptive use to estimate a woman's total duration of ovulation, which was positively associated with ovarian cancer risk (p less than 0.001 for trend). These observations support the concept that the greater the duration of ovulation or accompanying endocrinologic phenomena, the greater a woman's risk for ovarian cancer.
Adult↗
Personal and environmental characteristics related to epithelial ovarian cancer. II. Exposures to talcum powder, tobacco, alcohol, and coffee.
Vaginal exposures to talc and other particulates may play an etiologic role in epithelial ovarian cancer. Surgical sterilization may protect against ovarian cancer by blocking entry of such particulates into the peritoneal cavity. The authors assessed histories of talcum powder use, tubal sterilization, and hysterectomy with ovarian conservation in 188 women in the San Francisco Bay Area with epithelial ovarian cancers diagnosed in 1983-1985 and in 539 control women. To investigate the roles of blood-borne environmental exposures on ovarian cancer risk, they assessed lifetime consumption of coffee, tobacco, and alcohol in these women. Of the 539 controls, 280 were hospitalized women without overt cancer, and 259 were chosen from the general population by random digit telephone dialing. Ninety-seven (52%) of the cancer patients habitually used talcum powder on the perineum, compared with 247 (46%) of the controls. Adjusted for parity, the relative risk (RR) = 1.40, p = 0.06. There were no statistically significant trends with increasing frequency or duration of talc use, and patients did not differ from controls in use of talc on sanitary pads and/or contraceptive diaphragms. Fewer ovarian cancer patients (7%) than controls (13%) reported prior fallopian tube ligation (RR, adjusted for parity, = 0.56, p = 0.06), and fewer patients (20%) than controls (28%) reported prior hysterectomy (RR = 0.66, p = 0.05). The protective effect of hysterectomy was confined to those who underwent this surgery 10 or more years prior to interview and to those who had not undergone prior tubal sterilization. Consumption of cigarettes and alcohol did not differ between cases and controls. By contrast, 11 (6%) cases never regularly consumed coffee, compared with 31 (11%) hospital controls and 26 (10%) population controls (RR, adjusted for smoking, = 2.2, p = 0.03, for the comparison using all controls). Overall, ovarian cancer risk among women who had drunk coffee for more than 40 years was 3.4 times that of women who had never regularly consumed coffee (p less than 0.01). However, the data exhibited no clear trends in risk with increasing consumption. Although risk ratios relating duration of coffee drinking to ovarian cancer were unaffected by adjustment for several characteristics, further study is needed to exclude potential confounding by other unmeasured characteristics.
Adult↗
Contributions of epidemiology to exercise science and cardiovascular health.
Much important information about the cardiovascular benefits and hazards of exercise requires the methods of epidemiology, i.e., the study in human populations of frequencies and distributions of disease in terms of time, place, and personal characteristics. The key techniques are comparison and contrast, but epidemiological analyses of physical activity and cardiovascular health often must rely on circumstantial evidence to assess cause-and-effect relationships. The study procedures must be designed to meet rigorous epidemiological principles: statistical association, temporal sequence, consistency, persistence, independence, dose-response relationship, specificity, alterability, repeatability, and confirmation of findings. Through measurement and contrast, study procedures aim to determine whether physically active persons experience a lower incidence of cardiovascular disease than do persons more sedentary. Based on these principles, current evidence indicates that exercise induces protective benefits against coronary heart disease that enable most persons to approach their potential longevity.
Actuarial Analysis↗
Heart rate and cardiovascular mortality: the Framingham Study.
The relation of resting heart rate on biennial ECG examinations to mortality rates over 30 years of follow-up of the Framingham cohort was examined based on 1876 total deaths and 894 cardiovascular deaths, evolving out of 5070 subjects free of cardiovascular disease at entry into the study. In both sexes, at all ages, all-cause, cardiovascular, and coronary mortality rates increased progressively in relation to antecedent heart rates determined biennially. A more impressive association to cardiovascular disease was observed in men than in women, which was independent of associated cardiovascular risk factors. Case fatality rates following coronary events also increased with antecedent heart rate and the fraction of coronary deaths as sudden death increased strikingly with heart rate in men 35 to 64 years of age. There was also a substantial excess of noncardiovascular deaths at high heart rates, and the proportion of all deaths resulting from cardiovascular disease did not increase with heart rate. The excess cardiovascular deaths with more rapid heart rates were also noted, excluding those with interim overt cardiovascular disease, suggesting an effect independent of preexisting cardiac damage.
Adult↗