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Andrea K. Chomistek, Eric J. Shiroma and I-Min Lee

Background:

Physical activity is important for maintaining healthy weight. The time of day when exercise is performed—a highly discretionary aspect of behavior—may impact weight control, but evidence is limited. Thus, we examined the association between the timing of physical activity and obesity risk in women.

Methods:

A cross-sectional analysis was conducted among 7157 Women’s Health Study participants who participated in an ancillary study begun in 2011 that is measuring physical activity using accelerometers. The exposure was percentage of total accelerometer counts accumulated before 12:00 noon and the outcome was obesity.

Results:

Mean (±SD) BMI among participants was 26.1 (±4.9) kg/m2 and 1322 women were obese. The mean activity counts per day was 203,870 (±95,811) of which a mean 47.1% (±11.5%) were recorded in the morning. In multivariable-adjusted models, women who recorded < 39% (lowest quartile) of accelerometer counts before 12:00 noon had a 26% higher odds of being obese, compared with those recording ≥ 54% (highest quartile) of counts before noon (P trend = 0.02).

Conclusions:

These study findings—that women who are less active during morning hours may be at higher risk of obesity—if confirmed can provide a novel strategy to help combat the important health problem of obesity.

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Ralph S. Paffenbarger Jr., Jeremy N. Morris, William L. Haskell, Paul D. Thompson and I-Min Lee

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Maria Laura Resem Brizio, Pedro C. Hallal, I-Min Lee and Marlos Rodrigues Domingues

Background:

The aim of this study was to investigate the association between lifetime physical activity and risk of lung cancer.

Methods:

A case-control study was conducted in southern Brazil. Case subjects were recruited from oncology services of 4 hospitals. Control subjects were selected from the same hospitals, but from different services (traumatology and emergency). Both case subjects (n = 81) and control subjects (n = 168) were interviewed using a questionnaire about sociodemographic characteristics, anthropometric information and family history of cancer. Control subjects were matched to case subjects according to sex and age (± 5 years). Detailed information on smoking was collected. Physical activity was measured using the Lifetime Physical Activity Questionnaire.

Results:

Of the case subjects, 89% were either current or former smokers; among control subjects, this value was 57%. Participants in the second, third, and fourth quartiles of all-domains physical activity had odds ratios of 0.54 (95% CI, 0.21–1.40), 0.25 (95% CI, 0.08–0.72), and 0.24 (95% CI, 0.07–0.83) for lung cancer, compared with the lowest quartile, after adjusting for confounding. In the fully adjusted models, leisure-time physical activity was not associated with lung cancer risk.

Conclusion:

Lifetime all-domains physical activity may reduce the risk of lung cancer.

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I-Min Lee, Kathleen Y. Wolin, Sarah E. Freeman, Jacob Sattlemair and Howard D. Sesso

Background:

The number of cancer survivors is increasing rapidly; however, little is known about whether engaging in physical activity after a cancer diagnosis is associated with lower mortality rates in men.

Methods:

We conducted a prospective cohort study of 1021 men (mean age, 71.3 years) who were diagnosed with cancer (other than nonmelanoma skin cancer). Men reported their physical activities (walking, stair climbing, and participation in sports and recreational activities) on questionnaires in 1988, a median of 6 years after their cancer diagnosis. Physical activity was updated in 1993 and men were followed until 2008, with mortality follow-up > 99% complete, during which 777 men died (337 from cancer, 190 from cardiovascular disease).

Results:

In multivariate analyses, the relative risks for all-cause mortality associated with expending < 2100, 2100–4199, 4200–8399, 8400–12,599, and ≥ 12,600 kJ/week in physical activity were 1.00 (referent), 0.77, 0.74, 0.76, and 0.52, respectively (P-trend < 0.0001). Higher levels of physical activity also were associated with lower rates of death from cancer and cardiovascular disease (P-trend = 0.01 and 0.002, respectively).

Conclusions:

Engaging in physical activity after cancer diagnosis is associated with better survival among men.

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Larissa Roux, Mike Pratt, I-Min Lee, Terry Bazzarre and David Buchner

Background:

Community-based efforts to promote physical activity (PA) in adults have been found to be cost-effective in general, but it is unknown if this is true in middle-age specifically. Age group-specific economic evaluations could help inform the design and delivery of better and more tailored PA promotion.

Methods:

A Markov model was developed to estimate the cost-effectiveness (CE) of 7 exemplar community-level interventions to promote PA recommended by the Guide to Community Preventive Services, over a 20-year horizon. The CE of these interventions in 25- to 64-year-old adults was compared with their CE in middle-aged adults, aged 50 to 64 years. The robustness of the results was examined through sensitivity analyses.

Results:

Cost/QALY (quality-adjusted life year) of the evaluated interventions in 25- to 64-year-olds ranged from $42,456/QALY to $145,868/QALY. Interventions were more cost-effective in middle-aged adults, with CE ratios 38% to 47% lower than in 25- to 64-year-old adults. Sensitivity analyses showed greater than a 90% probability that the true CE of 4 of the 7 interventions was below $125,000/QALY in adults aged 50 to 64 years.

Conclusion:

The exemplar PA promotion interventions evaluated appeared to be especially cost-effective for middle-aged adults. Prioritizing such efforts to this age group is a good use of societal resources.

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Susumu S. Sawada, I-Min Lee, Hisashi Naito, Koji Tsukamoto, Takashi Muto and Steven N. Blair

Background:

Limited data are available on the relationship between muscular and performance fitness (MPF) and the incidence of type 2 diabetes.

Methods:

A cohort of 3792 Japanese men completed a medical examination that included MPF and cardiorespiratory fitness tests. MPF index composite score was calculated using Z-scores from vertical jump, sit-ups, side step, and functional reach tests.

Results:

The mean follow-up period was 187 months (15.6 years). There were 240 patients who developed type 2 diabetes during follow-up. Relative risks and 95% confidence intervals (CI) for incidence of diabetes across baseline quartiles of MPF index composite score were obtained using the Cox proportional hazards model while adjusting for age, BMI, diastolic blood pressure, cigarette smoking, alcohol intake, and family history of diabetes. The relative risks for developing diabetes across quartiles of MPF index composite scores (lowest to highest) were 1.0 (referent), 1.15 (95% CI 0.83−1.60), 1.10 (0.78−1.55), and 0.57 (0.37−0.90) (P for trend = .061). These results were attenuated after adjustment for cardiorespiratory fitness (P for trend = .125).

Conclusions:

This prospective study suggests that MPF is a predictor of type 2 diabetes, although its predictive ability was attenuated after adjusting for cardiorespiratory fitness.

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Yuko Oguma, Yusuke Osawa, Michiyo Takayama, Yukiko Abe, Shigeho Tanaka, I-Min Lee and Yasumichi Arai

Background:

To date, there is no physical activity (PA) questionnaire with convergent and construct validity for the oldest-old. The aim of the current study was to investigate the validity of questionnaire-assessed PA in comparison with objective measures determined by uniaxial and triaxial accelerometers and physical performance measures in the oldest-old.

Methods:

Participants were 155 elderly (mean age 90 years) who were examined at the university and agreed to wear an accelerometer for 7 days in the 3-year-follow-up survey of the Tokyo Oldest-Old Survey of Total Health. Fifty-nine participants wore a uniaxial and triaxial accelerometer simultaneously. Self-rated walking, exercise, and household PA were measured using a modified Zutphen PA Questionnaire (PAQ). Several physical performance tests were done, and the associations among PAQ, accelerometer-assessed PA, and physical performances were compared by Spearman’s correlation coefficients.

Results:

Significant, low to moderate correlations between PA measures were seen on questionnaire and accelerometer assessments (ρ = 0.19 to 0.34). Questionnaireassessed PA measure were correlated with a range of lower extremity performance (ρ = 0.21 to 0.29).

Conclusions:

This PAQ demonstrated convergent and construct validity. Our findings suggest that the PAQ can reasonably be used in this oldest-old population to rank their PA level.

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Jungyun Hwang, I-Min Lee, Austin M. Fernandez, Charles H. Hillman and Amy Shirong Lu

Purpose: This study examined differences in energy expenditure and bodily movement among children of different weight status during exergames that varied in mode and intensity. Methods: Fifty-seven 8- to 12-year-old children including overweight/obesity (n = 28) and normal weight (n = 29) played three 10-minute interval Xbox One exergames (Fruit Ninja, Kung-Fu, and Shape Up) categorized based on predominantly upper-, whole-, or lower-limb movement, respectively. The authors measured bodily movement through accelerometry and obtained energy expenditure and metabolic equivalent (MET) via indirect calorimetry. Results: Energy expended during gameplay was the highest in Shape Up (P < .01) and higher in Kung-Fu than Fruit Ninja (P < .01). Absolute energy expenditure was significantly higher in overweight/obese children (P < .01), but not when controlling for body mass across 3 exergames (P > .05). Based on the MET cut-points, overweight/obese children spent more time at light intensity (<3 METs) for Fruit Ninja (P < .05) and Shape Up (P < .01), but less time at vigorous intensity (≥6 METs) for Kung-Fu (P < .01) and Shape Up (P < .01). Lower-limb movements during Shape Up were less in overweight/obese children (P = .03). Conclusion: Although children in both groups expended similar energy relative to their body mass during gameplay, overweight/obese children spent more time at light intensity but less time at vigorous intensity with fewer movements especially while playing a lower limb–controlled exergame.

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I-Min Lee, Eric J. Shiroma, Kelly R. Evenson, Masamitsu Kamada, Andrea Z. LaCroix and Julie E. Buring

In recent years, it has become feasible to use devices for assessing physical activity and sedentary behavior among large numbers of participants in epidemiologic studies, allowing for more precise assessments of these behaviors and quantification of their associations with health outcomes. Between 2011–2015, the Women’s Health Study (WHS) used the Actigraph GT3X+ device to measure physical activity and sedentary behavior over seven days, during waking hours, among 17,708 women (M age, 72 years) living throughout the United States. Devices were sent to and returned by participants via mail. We describe here the methods used to collect and process the accelerometer data for epidemiologic data analyses. We also provide metrics that describe the quality of the accelerometer data collected, as well as expanded findings regarding previously published associations of physical activity or sedentary behavior with all-cause mortality during an average follow-up of 2.3 years (207 deaths). The WHS is one of the earliest “next generation” epidemiologic studies of physical activity, utilizing wearable devices, in which long-term follow-up of participants for various health outcomes is anticipated. It therefore serves as a useful case study in which to discuss unique challenges and issues faced.