Caroline A. Macera

Past recreational physical activity and risk of breast cancer.

Objective:To examine the association between baseline and earlier recreational physical activity and incidence of breast cancer in postmenopausal women. Design:Multicenter cohort study. Setting:Women were enrolled in the Womens Health Initiative Observational Study (WHIOS) at 40 clinical centers between October 1993 and December 1998. Participants:Of a total of 93676 women enrolled in the WHIOS, 74171 were included in this analysis. Eligibility criteria were: aged 50 to 79 years, postmenopausal, and free of serious health conditions that might reduce survival during the following 3 years. Women were excluded if they reported a history of breast cancer or had missing physical activity data. Women of non-European extraction made up 15% of the sample. By February 28, 2002, 3.2% were lost to follow-up and 2.7% had died. Assessment of risk factors:Participants completed baseline questionnaires that included information on medical and reproductive history, and health behaviors including physical activity and diet. Staff collected anthropometric data and information on use of hormone therapy. Women were asked if they usually exercised enough to work up a sweat ≥3 times per week at ages 18, 35, and 50 years. Current (baseline) walking for ≥10 minutes and participation in leisure-time activities were categorized by frequency, duration, and intensity. A current total activity variable was computed from the product of metabolic equivalent values and duration (MET h/wk). Main outcome measures:The main outcome measure was the association of incident breast cancer with measures of physical activity during a mean period of follow-up of 4.7 years. Cases of breast cancer were ascertained by the methods of the National Cancer Institute Surveillance, Epidemiology, and End Results guidelines, and collated by physicians and cancer coders blinded to exposure data. Main results:During follow-up, 1780 incident cases of breast cancer were documented. Women who had engaged in strenuous physical activity ≥3 times per week at age 35 had a decreased risk of breast cancer (multivariate adjusted relative risk [RR], 0.86; 95% CI, 0.78-0.95) compared with women who had not. The association was not significant for strenuous activity at age 50 or age 18 years. A greater amount of total current (baseline) physical activity was associated with a lower risk of breast cancer (P for trend, 0.03). Compared with no current physical activity, risk was reduced 18%, 11%, 17%, and 22% for women who exercised 5.1-10, 10.1-20, 20.1-40, and >40 MET h/wk. Hours of current moderate or strenuous physical activity was not significantly related to risk of breast cancer (P for trend, 0.12), although the highest duration category, >7 h/wk, compared with 0 h/wk showed a significant reduction in risk (RR, 0.79; CI, 0.63-0.99). When the women were divided by tertiles of body mass index (BMI cut points at 24.13 and 28.44 kg/m2), increased total current activity was protective against breast cancer for those in the lowest tertile of BMI (P for trend, 0.03) but not for those in the upper tertiles (P for trend, 0.74 and 0.30). Conclusions:More physical activity was associated with a lower risk of breast cancer in postmenopausal American women. An hour every day of moderate or strenuous activity provided most benefit.

Muscular strength and mortality in men.

Objective: To examine the associations between muscular strength and all-cause, cardiovascular, and cancer mortality among men. Design: Cohort study that followed a subgroup of participants in the Aerobics Center Longitudinal Study (ACLS). Setting: Cooper Clinic, Dallas, Texas, with a baseline of 1980 to 1989, and follow-up to December 31, 2003. Participants: Male participants in the ACLS, aged 20 to 90 years, were included after a clinical examination unless they failed to achieve

Exercise and risk of hip fracture in postmenopausal women.

85% of agepredicted maximal heart rate during a treadmill test; had an abnormal resting or exercise electrocardiogram, a history of myocardial infarction, stroke, or cancer; or had a body mass index ,18.5 kg/m. The subcohort included 8762 (85%) of 10 265 men who were predominantly white, well educated, and in the middle and upper socioeconomic strata. Assessment of risk factors: Muscular strength in the upper and lower body was measured on variable-resistance weight machines using a standardized strength testing protocol. Upper body strength and lower body strength were defined by a 1-repetition maximum supine bench press and seated leg press, respectively, after adding weights at successive trials. A measurement of strength was derived from the mean of the standardized scores for upper and lower body strength. Participants were divided into thirds by strength. Cardiorespiratory fitness was assessed by a maximal treadmill test to volitional exhaustion. Main outcome measures: The main outcome measures were the associations between muscular strength and all-cause, cardiovascular, and cancer mortality. Mortality and causes of death were ascertained from the National Death Index and death certificates. Main results: During a mean follow-up of 18.9 years and 165 251 person years, 503 deaths (5.7%) occurred, 145 (28.8%) from cardiovascular disease and 199 (39.6%) from cancer. Age-adjusted death rates per 10 000 person years were 38.9 for the least strong third, 25.9 for the middle third and 26.6 for the strongest third. The stronger two-thirds of participants had lower mortality hazard ratios (HR) in 3 progressively adjusted models [adjustment for all variables including cardiorespiratory fitness, middle third, HR, 0.74 (95% CI, 0.59–0.91) and strongest third, HR, 0.80 (CI, 0.64– 0.996); P for linear trend, 0.03]. HR for death from cardiovascular disease were not significant after multivariable adjustment [age-adjusted HR, middle third, 0.63 (CI, 0.43–0.93) and strongest third, HR, 0.55 (CI, 0.37–0.82); P for linear trend, 0.003]. For cancer mortality, risk remained lower in the multivariable model for the stronger two thirds [HR, middle third, 0.71 (CI, 0.50–0.996) and HR, strongest third, 0.67 (CI, 0.47–0.96); P for linear trend, 0.02]. Rates of allcause mortality were higher for the least strong third in the age group ,60 years as well as for men older than 60 years (P = 0.001 and P = 0.005 for linear trend, respectively), as were rates of cancer mortality (P = 0.02 and P = 0.007 for linear trend, respectively). Strength was inversely related to mortality among men with body mass index of , 25 kg/m and

Housework Will Not Prevent Death in Middle Age but Sports and DIY Might.

25 kg/m (P for linear trend, ,0.05). Conclusions: Muscular strength was independently inversely related to allcause and cancer mortality among men. The association persisted in younger and older men and normal weight and overweight men. Death from cardiovascular disease was linearly but not independently inversely related to strength. COMMENTARY The study by Ruiz et al highlights the value of muscular strength beyond the known benefits related to function, particularly among older adults. Although these results are from a select subset of the population (educated white men of middle to upper socioeconomic status), they provide insight as to how muscular strength and cardiorespiratory fitness contribute to all-cause, cardiovascular, and cancer mortality. This is extremely important because we are unlikely to obtain the detailed clinical measures described here on a large general population. Because these men, healthy at the time of the clinic visit (which occurred an average of 18.9 years before death or the end of the study) appear to be similar to samples in studies of other populations, their experience is valuable and may ultimately prove to apply to women, low socioeconomic groups, and ethnically diverse groups. One of the takeaway messages of this analysis is that resistance training should not be ignored as health and fitness goals are developed. The most obvious benefits appear to accrue among those aged 60 years and older, but these data reflect age at death and the measurement of strength and fitness may have occurred much earlier. Previous health recommendations focused on cardiorespiratory fitness, but, if the data from this study hold, it may be important to consider adding muscular strength recommendations, not only for older adults, but for all adults. In fact, in 2008 the US Department of Health and Human Services issued new Physical Activity Guidelines for Americans that encourage adding strengthening exercises for both adults and children. Whereas fitness may be more important than strength for cardiovascular mortality, the combination of strength and fitness is important for cancer and all-cause mortality. However, it appears as if the lower levels of fitness (bottom 20% of population) and/or strength (bottom 33% of population) are at particular risk. The encouraging part of this story is that reductions in mortality occur with at least a moderate level of fitness and/or strength, which should be an attainable goal for most people. Source of funding for the original study: National Institutes of Health, Spanish Ministry of Education, the Margit and Foke Pehrzon Foundation, the European Union, the American Heart Association, and the American College of Sports Medicine Paffenbarger-Blair Fund. Correspondence about the original study: J.R. Ruiz (e-mail: ruiz@ugr.es).

An hour of physical activity per day helps to keep weight gain at bay.

ObjectiveTo assess the association of exercise and leisure-time activity with risk of hip fracture in postmenopausal women. DesignCohort study. SettingThe Nurses Health Study (registered nurses in 11 states of the United States) was initiated in 1976. This analysis has a 1986 baseline and follow-up to June 1, 1998. ParticipantsRegistered nurses (age in 1976, 30–55 y; n = 121,700) returned initial questionnaires that included questions on medical history, lifestyle, and other risk factors related to cancer and heart disease. Postmenopausal respondents to the 1986 biannual questionnaire who had not reported a previous hip fracture or a diagnosis of cancer, heart disease, stroke, or osteoporosis and who completed the questions on physical activity were included (n = 61,200). Assessment of risk factorsParticipants reported the average amount of time per week during the previous year spent in 7 activities (walking [and walking pace], jogging, running, bicycling, racquet sports, lap swimming, and other aerobic activity) in 1986, 1988, 1992, 1994, and 1996. Additional vigorous activities and lower intensity activities (e.g., yoga) were included on the 1992 to 1996 questionnaires. Metabolic equivalent (MET) hours per week were calculated and cumulatively averaged. Change from 1980 to 1986 was calculated from less detailed activity questions in 1980. Inactivity (hours spent sitting and standing) was also assessed. Main outcome measuresThe main outcome measure was risk of self-reported hip fracture resulting from low or moderate trauma (e.g., slipping on ice, falling from the height of a chair) during 12 years of follow-up in relation to quintiles of activity (least, <3 MET; most, ≥24 MET h/wk). Main resultsThe women in the study were fairly sedentary (median activity, 7 MET h/wk; 19% reported <15 min/wk of leisure-time physical activity). In multivariate analysis, the 3 quintiles whose activity level was ≥9 MET h/wk had progressively lower relative risk (RR) of hip fracture in comparison with the least active quintile (RR [95% CI], 0.67 [0.49–0.92], 0.53 [0.37–0.74], and 0.45 [0.32–0.63], respectively; P for trend through all quintiles, <0.001). Higher body mass index was also independently associated with lower risk of fracture (P for trend, <0.001). In the lowest activity quintile, hormone replacement therapy lowered the risk for hip fracture (RR, 0.45 [0.26–0.78]), but there was little further risk reduction for more active women (P for trend, 0.24). Among women who increased their physical activity between 1980 and 1986 from <1 h/wk to ≥4 h/wk, risk for fracture was lower (P for trend, 0.07), whereas among women whose activity level decreased from ≥4 h/wk, RR doubled for those active <1h/wk in 1986 (2.08 [1.20–3.61]; P for trend through all quintiles, 0.004). Longer duration and faster pace of walking among women who engaged in walking as their only physical activity lowered risk of fracture (RR for ≥4 h/wk vs. <1 h/wk, 0.59 [0.37–0.94], and RR for brisk pace vs. easy pace, 0.35 [0.22–0.55]). ConclusionsModerate levels of physical activity and walking were associated with fewer hip fractures among post-menopausal women.

Obesity, physical activity, and the risk of decline in health and mobility.

Objective: To examine the associations of mortality with intensity and type of physical activity. Design: Cohort study, with a mean follow-up of 9.6 years. Setting: Community study of civil servants in London, United Kingdom (the Whitehall Cohort Study, which commenced in 1985). Participants: The study population comprised 7456 participants (72% of the original cohort) who had complete data on baseline measures of physical activity and all covariates from phase 5 (1997-1999; mean age of participants, 56 years) and/or phase 7 (2002-2004; mean age, 61 years). Assessment of Risk Factors: The baseline examinations included a postal questionnaire and a clinical examination. Questions on physical activity included both work and free time activity; 20 items evaluated time spent during the previous 4 weeks in walking, specific and other sports, gardening, housework, and do-it-yourself (DIY) activities. Metabolic equivalent hours per week (MET) were assigned to reflect mild activity, moderate activity, and vigorous activity (,3, 3-5.9, and

Changes in physical activity and mortality in older women.

6 MET). Sociodemographic and lifestyle factors were assessed, and health history was recorded. Main Outcome Measures: The main outcome measures were the associations of intensity and type of self-reported physical activity with mortality. Mortality follow-up on April 30, 2009, by means of the national mortality register, was 99.9% complete. Main Results: During follow-up, 317 deaths (4.3%) occurred. In analysis adjusted for all covariates, mild physical activity for 5.5 to 8.9 hours per week or for

Moderate to vigorous exertion and sudden cardiac death in women.

9 hours did not lower hazard ratios (HR) for mortality (P for trend, 0.64) compared with ,5.5 hours of mild activity. More hours of moderate physical activity (1.0-3.4 and

Weight loss, physical activity, and weight regain in postmenopausal women.

3.5 hours per week vs ,1 hour) were associated with lower mortality (HR, 0.67; 95% confidence interval [CI], 0.510.88, and HR, 0.67; 95% CI, 0.500.91, respectively). More hours of vigorous activity (0.1-0.9 and

Cardiorespiratory Fitness and Prostate Cancer

1.0 hour per week vs 0 hours) were not associated with lower mortality (P for trend, 0.32). In age-adjusted analysis, all types of physical activity except housework (walking, sports, gardening, and DIY) were associated with lower mortality. After adjustment for covariates, including other types of physical activity, 0.1 to 1.9 hours per week and