Recreational physical activity and risk of papillary thyroid cancer among women in the California Teachers Study

Purpose: Little is known about the relationship between physical activity and thyroid cancer risk, and few cohort data on this association exist. Thus, the present study aimed to prospectively examine long-term activity and risk of papillary thyroid cancer among women. Methods: 116,939 women in the California Teachers Study, aged 22–79 years with no history of thyroid cancer at cohort entry, were followed from 1995–1996 through 2009; 275 were diagnosed with invasive papillary thyroid cancer. Cox proportional-hazards regression provided relative risk (RR) estimates and 95% confidence intervals (CI) for associations between thyroid cancer and combined strenuous and moderate recreational physical activity both in the long-term (high school through age 54 years or current age if younger than 54 years) and recently (during the three years prior to joining the cohort). Results: Overall, women whose long-term recreational physical activity averaged at least 5.5 MET-hours/week (i.e. were active) had a non-significant 23% lower risk of papillary thyroid cancer than inactive women (RR = 0.77, 95% CI: 0.57, 1.04). RR estimates were stronger among normal weight or underweight women (body mass index, BMI < 25.0 kg/m², trend p = 0.03) than among overweight or obese women (trend p = 0.35; homogeneity-of-trends p = 0.03). A similar pattern of risk was observed for recent activity (BMI < 25 kg/m², trend p = 0.11; BMI ≥ 25 kg/m², trend p = 0.16; homogeneity-of-trends p = 0.04). Associations for long-term activity did not appear to be driven by activity in any particular life period (e.g. youth, adulthood). Conclusions: Long-term physical activity may reduce papillary thyroid cancer risk among normal weight and underweight women.     

Knowledge and awareness of heat-related morbidity among adult recreational endurance athletes

Adults have been increasingly motivated to compete in recreational endurance sports events. Amateurs may lack a complete understanding of recommended strategies for handling heat and humidity, making heat-related illnesses increasingly possible. This is compounded by global climate change and increasing average surface and air temperatures, especially in urban areas of industrialized nations in Europe and North America that have hosted most events to date. We conducted an on-line, secure survey at the 2nd Annual ING Georgia Marathon and Half-Marathon in Atlanta, Georgia, in 2008. We included previously validated questions on participant socio-demographics, training locations, and knowledge and awareness of heat-related illnesses. Participants were aware of heat illnesses, and of heat stroke as a serious form of heat stress. However, the majority, across age and gender, did not understand the potential severity of heat stroke. Furthermore, 1-in-5 participants did not understand the concept of heat stress as a form of heat-related illness, and how heat stress may result from buildup of muscle-generated heat in the body. Adult recreational endurance athletes are another susceptible, vulnerable population sub-group for applied research and public health educational interventions, especially in urban areas of industrialized nations in Europe and North America.     

Diabetes,physical activity and breast cancer among Hispanic women

Purpose: We assessed the association between diabetes and breast cancer and whether physical activity modified the effect of diabetes on breast cancer in Hispanic women. Methods: We used data from a case-control study of breast cancer among Hispanic women aged 30–79 conducted between 2003 and 2008 on the Texas–Mexico border. In-person interviews were completed with 190 incident breast cancer cases ascertained through surgeons and oncologists, and 979 controls who were designated as both high-risk (n = 511) and low-risk (N = 468) for breast cancer (with respective response rates of 97%, 83% and 74%). Results: After adjustment for menopausal status and mammography screening, there was no effect of diabetes on breast cancer risk (high-risk control group odds ratio [OR] 1.02, 95% confidence interval [CI] 0.71–1.48; low-risk control group OR 0.87, 0.58–1.30). Women who had a diabetes history and did not exercise were at no risk of breast cancer (OR 0.96, 95% CI 0.63–1.48) or a slightly reduced breast cancer risk (low-risk control group OR 0.72, 95% CI 0.46–1.15) depending on the control group used, while women with diabetes who did exercise had significantly reduced breast cancer risk (OR 0.41, 95% CI 0.21–0.83) regardless of the control group used (high-risk control group p-value for interaction = 0.013, low-risk control group p-value for interaction 0.183). Conclusions: Should other studies confirm our results, physical activity should be explored as a means of reducing breast cancer risk in diabetic women.     

Occupational physical activity and risk of coronary heart disease among active and non-active working-women of North Dakota: a Go Red North Dakota Study

Currently less than half of the US adults meet physical activity (PA) recommendations, yet many more are sedentary in their occupations. Sedentary workers may therefore be at elevated risk for coronary heart disease (CHD). Therefore, the objective of the study is to examine the relationship of CHD risk with occupational PA (OCPA) and leisure time PA (LTPA) among working-women. The 10-year CHD risk and relative risk scores were calculated for 642 working-women. Self-report questionnaire determined levels of OCPA and LTPA. Biometric data were directly collected on all women. No direct relationship for OCPA and 'high risk' of CHD was determined. Insufficient LTPA was significantly associated with greater prevalence of 'high risk' of CHD. No dose response relationship was determined with PA and CHD risk. The odds of being 'high risk' were significantly greater for sedentary workers with insufficient LTPA compared to sufficient LTPA. The odds for being 'high risk' were similar among moderately active or heavy working women completing insufficient LTPA compared to women doing sufficient LTPA. For women with sedentary occupations, a sufficient amount of LTPA is essential to reduce CHD risk. Women in moderate to heavy working occupations may be acquiring adequate amounts of PA to minimize CHD risk.     

Study of coronary risk factors related to physical activity in 15 171 men.

Physical activity, both at work and during leisure, was assessed in 15 171 men aged 25-74 years. Heavy leisure activity was associated with lower mean serum cholesterol levels and blood pressure. In men under 60 years the same negative association was also noted between leisure activity and relative weight and cigarette smoking. Different degrees of physical activity at work were not associated with any differences in these risk factors, nor did the level of exercise at work seem to influence the negative association between leisure activity and risk factors. Heavy leisure activity in young and middle-aged men is associated with lower levels of certain coronary risk factors and, therefore, a lower risk of coronary heart disease. The often-reported reduction in coronary morbidity and mortality with physical exercise may not be the direct effect of the exercise itself.     

Post-heparin hepatic lipase activity and plasma high density lipoprotein levels in men during physical training

Plasma post-heparin hepatic lipase (PHHL) activity, plasma lipids, and high density lipoprotein cholesterol (HDL-C) levels, pulse rate at submaximal workload, and body weight were measured in 12 men during the 18 weeks physical training for their first marathon run. Reduced pulse rate at submaximal workload indicated that the men increased their physical fitness during the training period. Plasma HDL-C levels (+27%) and PHHL activity (+29%) also increased significantly after 18 weeks training. These changes were not in accord with the inverse correlation between plasma HDL-C levels and PHHL activity which was observed before training. The results of this study do not support the concept that reduced PHHL activity is mainly responsible for increased levels of plasma HDL-C with training.     

Synergistic effect between alcohol consumption and familial susceptibility on lung cancer risk among Chinese men

We aimed to examine the effect of alcohol consumption on lung cancer risk stratified by smoking, and to explore whether the impact of alcohol was modified by familial susceptibility to cancer. We recruited 1208 male lung cancer incident cases and 1069 community referents during 2004–2006 and collected their lifetime history of alcohol consumption, cigarette smoking, and family cancer history. Unconditional multivariate logistic regression analysis was performed to estimate the adjusted odds ratio (OR). We tested multiplicative-scale interaction between exposures of interest and examined the additive-scale interaction using synergy index. A moderate association between frequent alcohol consumption and lung cancer was observed among men who had family cancer history (OR = 4.22, 95%CI: 2.46–7.23) after adjustment of smoking and other confounders, while the alcohol effect among men without family history was weak (OR = 1.24, 95%CI: 0.95–1.63) and it became no excess in the never smokers. We observed a consistent synergistic effect between alcohol drinking and family cancer history for all lung cancers and the adenocarcinoma, while there was no multiplicative-scale interaction between the exposures of interest (likelihood ratio test for interaction, p>0.05). Our study revealed a possible synergistic effect between alcohol consumption and familial susceptibility for lung cancer risk; however, this observed possible association needs to be confirmed by future larger analytic studies with more never smoking cases.     

Circadian rhythm mediates the relationship between physical activity and quality of life in younger and older cancer survivors

Increasing evidence suggests that physical activity (PA) improves the quality of life (QoL) of cancer survivors. However, the biological mechanisms underlying the relationship between PA and QoL are unclear. The purpose of this study was to determine whether the relationship between PA and QoL differs in younger and older cancer survivors and whether circadian rhythm (CR) mediates this relationship. We also explored the effect of the CR on QoL. The participants were 235 cancer survivors, comprising 143 younger and 92 older patients. Data were collected using the Taiwanese versions of the Physical Activity Scale for the Elderly and Short Form-36. The robustness and stability of the CR were measured using an actigraph. Mediation was tested using multiple mediation analyses. The CR mediated the relationship between PA and the physical domain of QoL in younger and older cancer survivors (23% and 59% mediating effects, respectively). The CR partially mediated the effect of PA on the mental dimension of QoL in older cancer survivors (36% mediating effect), but not in younger cancer survivors. Cancer survivors with a more robust CR had a significantly higher QoL, particularly in the physical functioning domain (d?=?0.43, p?<?0.001). The results provided evidence that the CR mediated the relationship between PA and QoL. Moreover, this mediating effect differed in younger and older cancer survivors. These results can serve as a reference for designing individualized PA programs for cancer survivors.     

Changes in nutrient intakes of conditioned men during a 5-day period of increased physical activity and other stresses

Nutrient intakes and selected blood and urinary constituents of 16 Navy servicemen were obtained before and during a period of 113 hours of physical activity, sleep deprivation, and psychological stress, to document the dietary adaptation of physically conditioned men to an extended period of hard physical work and other stresses. Food intakes were monitored by 1-day diet records prior to and by direct observation during the period. The factorial method was used to calculate energy expenditure. Carbohydrates provided 45 and 43% of the total energy intake before and during the experiment. Protein intakes and intakes of all the vitamins and minerals studied exceeded the Recommended Dietary Allowances, both before and during the period. Total energy intake averaged 18.7 MJ.d-1 before and 24.4 MJ.d-1 during the experiment. Body weight increased significantly by 2.7 +/- 0.4 kg (mean +/- s.e.) during the experiment (p less than 0.0001). There was a significant correlation (r = 0.74; p less than 0.001) between the change in body weight and urinary sodium from before to after the experiment suggesting that increased dietary sodium may have contributed to the weight gain. A significant increase in plasma volume (11.9 +/- 3.2%; p less than 0.0003) provided further support that the observed weight gain was due to sodium intake rather than a positive energy balance. In conclusion, conditioned men increased food consumption adequately to meet increased energy demands.     

Fetal and placental size and risk of hypertension in adult life.

OBJECTIVE--To study the effect of intrauterine growth and maternal physique on blood pressure in adult life. DESIGN--A follow up study of infants born 50 years previously whose measurements at birth were recorded in detail. SETTING--Preston, Lancashire. SUBJECTS--449 Men and women born in hospital in Preston during 1935-43 and still living in Lancashire. MAIN OUTCOME MEASURES--Placental weight, birth weight, and blood pressure at age 46 to 54 years. RESULTS--In both sexes systolic and diastolic pressures were strongly related to placental weight and birth weight. Mean systolic pressure rose by 15 mm Hg as placental weight increased from less than or equal to 1 lb (0.45 kg) to greater than 1.5 lb and fell by 11 mm Hg as birth weight increased from less than or equal to 5.5 lb to greater than 7.5 lb. These relations were independent so that the highest blood pressures occurred in people who had been small babies with large placentas. Higher body mass index and alcohol consumption were also associated with higher blood pressure, but the relations of placental weight and birth weight to blood pressure and hypertension were independent of these influences. CONCLUSIONS--These findings show for the first time that the intrauterine environment has an important effect on blood pressure and hypertension in adults. The highest blood pressures occurred in men and women who had been small babies with large placentas. Such discordance between placental and fetal size may lead to circulatory adaptation in the fetus, altered arterial structure in the child, and hypertension in the adult. Prevention of hypertension may depend on improving the nutrition and health of mothers.