Physical activity, diet and skeletal health

Low bone turnover levels predict increased risk of cancer

BACKGROUND

Several epidemiological studies have shown an association between bone mineral density (BMD) and risk of breast cancer in postmenopausal women, but it remains unknown whether bone turnover is associated with increased risk of cancer. The aim of this study was to investigate if markers of bone formation and resorption are associated with increased risk of cancer.

MATERIAL AND METHODS

The study population included 5855 postmenopausal Danish women enrolled in the Prospective Epidemiologic Risk Factor (PERF) study. Cancer diagnosis was obtained from the Danish Cancer Registry. Baseline spine, femur, and whole-body BMD were evaluated by DXA-scanners. Baseline bone turnover (CTX-1 and osteocalcin) were measured in serum. Multivariate Cox analysis was performed with 3, 6 and 12 years of follow-up. All continuous variables were transformed into z-score for the cox analyses.

RESULTS

252 developed cancer after 3 years, 462 developed cancer after 6 years, and 881 developed cancer with 12 years of follow-up. CTX-1, osteocalcin and spine BMD were all predictors of cancer at all time points (3 years of follow-up: Spine BMD, HR = 1.20, p = 0.003; CTX-1, HR = 0.82, p = 0.005; osteocalcin, HR = 0.75, p < 0.001). After adjusting for cancer risk factors and other bone measures CTX-1 and osteocalcin remained independent predictors of cancer (3 years of follow-up: CTX-1, HR = 0.82, p = 0.02; osteocalcin, HR = 0.75, p = 0.002).

CONCLUSIONS

We found that levels of the bone turnover markers CTX-1 and osteocalcin were inversely associated with risk of cancer independent of BMD and other known cancer risk factors in postmenopausal women.

MONITORING AND EVALUATION OF SPORTS LOAD FOR PRIMARY AND MIDDLE SCHOOL STUDENTS

In recent years, the physical fitness of primary and middle school students in China has been declining. In addition to the unbalanced nutrition, the main reason is the insufficient load of physical exercise. The aim of this study is to explore the quantitative methods of sports load of primary and middle school students by means of training impulse (TRIMP), and to evaluate the feasibility and effectiveness of this method. In the study, 297 students (168 boys, 129 girls) were divided into intervention group and control group. All of students were tested with height, weight, vital capacity, sit-and-reach, 50[Formula: see text]m running, 50[Formula: see text]m [Formula: see text] 8 round trip, one-minute sit-up, one-minute skip and other physical indicators in gym class, the change of resting heart rate, sport heart rate, exercise time were collected before and after by independent development of the heart-rate wrist belt. The mean sport heart rate, mean exercise time (the cumulative time of the heart rate between 120 and 200[Formula: see text]bpm), the time of different intensity exercise and the TRIMP were calculated. The results of correlation analysis showed that the change of TRIMP was positively correlated with the change of vital capacity and one-minute sit up, and increasing sports load could improve the physical health, verifying the feasibility of using the TRIMP to quantify the sports load. At the same time, the TRIMP was expressed in scores to make the understanding easy for the teachers and students or any audience in general.

Oral health behaviors and bone mineral density in South Korea: the 2008-2010 Korean National Health and Nutrition Examination Survey

The purpose of this study was to examine the association between oral health behaviors and bone mineral density (BMD) by using data from the Korean National Health and Nutrition Examination Survey conducted in 2008-2010. We included 6,620 subjects (3,140 men aged more than 50 years and 3,480 postmenopausal women). BMD was measured at three sites-namely, the lumbar spine, total femur, and femur neck. Oral health behaviors were assessed by use of a self-administered questionnaire in the Korean National Health and Nutrition Examination Survey. After adjustment for all covariates, BMD of the lumbar spine and femur neck tended to increase as the frequency of tooth brushing increased in men (p trend = 0.020 and p trend = 0.028, respectively). Women using secondary oral products had increased lumbar spine BMD compared with women who did not use secondary oral products. However, after adjustment for all covariates, no significant relationship was observed between BMD and the use of secondary oral products. As the frequency of tooth brushing and the number of secondary oral products used increased, the prevalence of osteoporosis decreased. The frequency of tooth brushing is associated with increased lumbar spine and femur neck BMD in South Korean men.

Effects of calcium and training on the development of bone density in children with Down syndrome

In this study we examined the effects of physical training and calcium intake on the development of bone mineral density (BMD) in children with Down syndrome (DS). A total of 48 children with DS (age 7-12 years old) matched for age and BMD were assigned to four groups exercise and calcium intake (Ex(+)Ca(+)), calcium intake-no-exercise (Ex(-)Ca(+)), exercise no-calcium intake (Ex(+)Ca(-)) and non-exercise-no-calcium intake (Ex(-)Ca(-)). The training protocol included 45 min of weight bearing exercise performed 3 sessions per week in addition to dietary calcium rich food intake of enriched cow milk with vitamin D containing 200 mg calcium per serving or no enriched dietary supplement for a duration of 4 months. Data analysis was performed on data by using t-test, one-way ANOVA analysis and Tukey post hoc tests to determine the main and combined effects of training and calcium regiment on BMD. All groups showed greater femoral neck BMD after 4 months. The increase in femoral neck BMD in the Ex(+)Ca(+) group was 5.96% greater than the Ex(+)Ca(-) group (p<0.01). The effect of training was greater than calcium intake alone. The Ex(+)Ca(-) group achieved 3.52% greater BMD than Ex(-)Ca(+) group (p<0.01). In this study, all the experimental groups had greater BMD than the no-calcium-no-exercise group that served as the control group (p<0.01). It was concluded that additional weight bearing exercise and calcium supplementation resulted in a greater increase in BMD in children with DS.

Bone mineral density changes after physical training and calcium intake in students with attention deficit and hyper activity disorders

In this study we investigate the effects of weight bearing exercise and calcium intake on bone mineral density (BMD) of students with attention deficit and hyper activity (ADHD) disorder. For this reason 54 male students with ADHD (age 8-12 years old) were assigned to four groups with no differences in age, BMD, calcium intake, and physical activity: exercise groups with or without calcium supplementation (Ex+Ca+ and Ex+Ca-) and non-exercise groups with or without calcium supplementation (Ex-Ca+ and Ex-Ca-). The intervention involved 50 min of weight bearing exercise performed 3 sessions a week and/or the addition of dietary calcium rich food using enriched cow milk with vitamin D containing 250 mg calcium per serving, over 9 months. Paired-samples t-test, one way ANOVA analysis, and Tukey tests were used to determine the main and combined effects of training and calcium on BMD. All groups showed greater femoral neck BMD after 9 months. The increase in femoral neck BMD was significantly different between all groups (p < 0.05). Ex+Ca+ group has greater increase in BMD than other groups. Apparently, the effect of training was greater than calcium intake (p < 0.05). These results help to provide more evidence for public health organizations to deal with both exercise and nutrition issues in children with ADHD disorder for the achievement of peak BMD.

Higher bone mineral density is associated with a decreased risk of colorectal adenomas

Bone mineral density (BMD) is a biomarker for cumulative exposure to multiple factors including estrogen, calcium, vitamin D and physical activity, which have all been independently associated with colorectal cancer. Furthermore, higher levels of BMD have been inversely associated with colorectal cancer risk, particularly in postmenopausal women. However, no prior studies have examined the potential association between BMD and colorectal adenomas, which are precursor lesions to most colorectal cancers. Therefore, we evaluated the association between BMD, which was measured using a whole body, dual-energy X-ray absorptiometry scan and colorectal adenomas in 167 patients who underwent colonoscopy screening. We found that patients in the highest tertile of total body BMD (>1.294 g/cm(2)) and in the middle tertile (≥1.167 to ≤1.294 g/cm(2)) compared to those with a total body BMD in the lowest tertile (<1.167 g/cm(2)) had a lower risk of colorectal adenomas (highest vs. lowest tertile: OR = 0.29 (0.10-0.84); middle vs. lowest tertile: OR=0.26 (0.08-0.80); p-trend=0.02). Stratification by gender revealed that this association was more pronounced in women (highest (>1.280 g/cm(2)) vs. lowest (<1.130 g/cm(2)) tertile: OR=0.08 (0.01-0.70); middle (≥1.130 to ≤1.280 g/cm(2)) vs. lowest tertile: OR=0.15 (0.04-0.94); p-trend=0.02) even after excluding hormone replacement therapy users (highest (>1.295 g/cm(2)) and middle (≥1.132 to ≤1.295 g/cm(2)) vs. lowest (<1.132 g/cm(2)) tertile: OR=0.17 (0.03-0.97); p-trend=0.04). Our results show, for the first time, that BMD is inversely associated with colorectal adenomas, particularly in women. Although additional larger, prospective studies are needed, our results suggest that BMD may be a biomarker for colorectal cancer precursor lesions.

The sports and exercise life-course: a survival analysis of recall data from Ireland

Recall data from a representative sample of 3080 adults in Ireland in 2003 is used to investigate transitions into and out of regular participation in sports and exercise--an important contributor to overall physical activity. The method produces a continuous picture of participation across the life-course, allowing key transition periods in the life-course to be identified and the determinants of transitions to be analysed with multivariate models. Late adolescence emerges as an important period, when many people drop out from team sports, especially females. Participation in adulthood mostly involves taking up individual sports and exercise activities. The likelihood of making this transition is strongly associated with socio-economic status. Transitions in activity during adulthood do not display significant sex differences, suggesting that the gender gap for involvement in sports and exercise has its roots in childhood. The method also allows age and cohort effects to be distinguished, revealing higher participation among more recent cohorts. The findings must be interpreted carefully, since they are reliant on the accuracy of personal recall. Yet they have implications for how physical activity policy applies over the life-course, suggesting possible returns to targeting lower socio-economic groups in early adulthood, to offering a broader range of activities to young females, and to researching and promoting those activities most likely to be of interest to current young adults as they age.

Association between levels of physical activity and poor self-rated health in Korean adults: The Third Korea National Health and Nutrition Examination Survey (KNHANES), 2005

OBJECTIVE

To investigate the association between level of physical activity and poor self-rated health in Korean adults.

STUDY DESIGN

A cross-sectional study was conducted on 7,800 adults aged > or =19 years who completed the Health Interview and the Health Behavior Surveys, issued during the Third National Health and Nutrition Examination Survey (2005).

METHODS

The association between self-rated health and physical activity was tested using Chi-squared test. Multiple logistic regression analysis was used to calculate the odds ratios of poor self-rated health for different levels of physical activity after adjusting for physical and chronic medical conditions.

RESULTS

The prevalence of poor self-rated health was significantly lower as the level of physical activity increased, and odds ratios for poor self-rated health were significantly lower for higher levels of physical activity after adjusting for age, marital status, educational status, smoking, alcohol consumption, and the number of physical impairments and chronic medical conditions. The association was similar in different age groups and among healthy respondents and respondents with physical impairments or chronic medical conditions.

CONCLUSIONS

Physical activity was positively associated with self-rated health in Koreans. The independent association between a lower level of physical activity and poor self-rated health supports public health programmes that encourage regular physical activity.

Skipping breakfast is associated with dysmenorrhea in young women in Japan

To evaluate the effects of breakfast habits on the quality of life in young women in Japan, the relation between breakfast habits and menstrual and intestinal disorders was estimated by responses to a questionnaire. Subjects were recruited from young Japanese female students of Ashiya College ranging in age from 18 to 20 years. Breakfast habits were classified into three groups (group I, having breakfast every morning, n=289; group II, having breakfast one to six times per week, n=106; group III, having breakfast less than once a week, n=44). The intensity of dysmenorrhea was classified into three grades (score 1, free of pain or painful, but without need for analgesic; score 2, painful, requiring analgesic; score 3, painful, not relieved by analgesic). The grades of bowel movement were classified into three groups (score 1, no more than once a week; score 2, two to six times a week; score 3, every day). Group II and group III had significantly higher scores for dysmenorrhea compared with group I. Students in group III showed a tendency toward constipation. Since dysmenorrhea is a risk factor for psychological disorders as well as gynecological diseases, the present study suggests the importance of eating breakfast to the quality of life of young women.

Diet during adolescence is a trigger for subsequent development of dysmenorrhea in young women

Recently many young women in Japan have been restricting their dietary intake for cosmetic purposes. In this study, the relation between diet and menstrual disorders was investigated by responses to a questionnaire. Subjects ranging from 18 to 20 years old were recruited from 716 female students at Ashiya College. Dietary habits were classified into group I (having no experience with dieting), group II (those currently on a diet) and group III (those with a history of dieting). The intensity of dysmenorrhea was classified into three grades. All participants were divided into two groups as having regular or irregular menstruation. The frequency of irregular menstruation in group II was higher than that in the other groups, while group III had higher intensity of dysmenorrhea than the other groups. These findings suggest that diet during adolescence has long-lasting adverse effects on reproductive function in young women.

Independent and combined effect of nutrition and exercise on bone mass development

Food intake provides the necessary components for adequate metabolic functions in bone. Calcium, phosphorus, vitamin D, magnesium, proteins, and fluoride are some of the most important nutrients in this regard. These have different effects on bone mass. Additionally, exercise has been shown to elicit osteogenic responses in bone development; indeed, it seems to potentiate, for example, the effect of calcium supplementation on bone mass. However, the nutrition-exercise-bone mass relationship is complex and needs further in-depth investigation. As a first step, therefore, we reviewed current knowledge about the role of nutrition on the development of bone tissue and how physical activity affects the nutrient-bone relationship.

Young Japanese college students with dysmenorrhea have high frequency of irregular menstruation and premenstrual symptoms

In this study, to estimate the current status of young women with menstrual disorders, the relation among dysmenorrhea, irregular menstruation and premenstrual symptoms was investigated by a questionnaire. Subjects ranging from 18 to 20 years old were recruited from 522 female students at Ashiya College in Japan. The intensity of dysmenorrhea was classified into 3 grades (score 1, not requiring analgesic; score 2, painful, requiring analgesic; score 3, painful, not relieved by analgesic). All participants were further divided into subsequent groups as having premenstrual symptoms or not and those having regular or irregular menstruation. Dysmenorrhea scores in the students with premenstrual symptoms or irregular menstruation were significantly higher than those without these symptoms (1.66±0.66 vs 1.41±0.59; 1.62±0.68 vs 1.49±0.61, respectively). There was no significant relation in the incidence between premenstrual symptoms and irregular menstruation. These findings suggest that considerable numbers of young women with dysmenorrhea are associated with premenstrual symptoms.

Physical activity, calcium intake and bone health in children and adolescents

Osteoporosis is a serious and potentially debilitating disease, which can lead to a variety of health complications and a diminished quality of life. Consequently, the development of bone mineral density (BMD) and content (BMC) during childhood and adolescence is of great importance, as it may attenuate the effects and incidence of osteoporosis later in life. Identifying the mechanisms by which bones are strengthened early in life is crucial. This review highlights research examining factors that influence BMD and BMC in children and adolescents. While a sizeable amount of variation in BMD and BMC in children and adolescents can be attributed to genetic factors and body size, studies have also shown the positive influence of physical activity and calcium intake on bone development. Research supporting the role of these modifiable factors varies according to age, sex and the bone site studied. During the pubertal years, large gains in BMD and BMC are evident. However, physical activity and calcium intake are also important to the development of BMD and BMC during the prepubertal years. Thus, actions taken throughout childhood may exert a great impact on BMD and BMC, and overall bone health as an adult.

Meeting adequate intake for dietary calcium without dairy foods in adolescents aged 9 to 18 years (National Health and Nutrition Examination Survey 2001-2002)

BACKGROUND

In the United States, >50% of dietary calcium is provided by milk and milk products. Calcium intakes in the United States are inadequate for many children, and a large proportion do not drink milk or consume dairy products. However, no studies have addressed whether dairy-free diets can provide adequate calcium while meeting other nutrient recommendations.

OBJECTIVE

To determine the highest calcium intake for adolescents obtained from dairy-free diets, and to examine the relationship between intakes of calcium-fortified foods, using citrus juice as an example, and maximal calcium intakes.

DESIGN

In the National Health and Nutrition Examination Survey 2001 to 2002, 65 females and 62 males, aged 9 to 18 years, reported no intake of dairy. We used linear programming to generate diets with maximal calcium intake, while meeting Dietary Reference Intakes for a set of nutrients, limiting energy and fat intakes, and not selecting food quantities exceeding amounts usually eaten in the population.

RESULTS

With food use and energy and fat constraints, diets formulated by linear programming provided 1,150 and 1,411 mg/day of calcium for girls and boys, respectively. With the Dietary Reference Intakes constraints, these decreased to 869 and 1,160 mg/day. When we introduced 1.5 servings of fortified juice to the diets, the highest calcium intake increased to 1,302 mg/day for girls and to 1,640 mg/day for boys.

CONCLUSIONS

Adequate intake for calcium cannot be met with dairy-free diets while meeting other nutrient recommendations. To meet the adequate intake for calcium without large changes in dietary patterns, calcium-fortified foods are needed. In addition, greater physical activity and responsible sunlight exposure should be encouraged to promote vitamin D adequacy.

Calcium Supplementation Increases Bone Mass in GH-Deficient Prepubertal Children during GH Replacement

BACKGROUND/AIMS

Since GH plays an important role in bone mineralization, and several studies demonstrated the positive influence of a higher calcium intake on bone mass, we studied the effect of calcium supplementation in GHD children during GH therapy.

METHODS

28 prepubertal GHD children, 5.0-9.9 years old, were assigned to two groups: group A (n = 14; 7 females) treated with GH, and group B (n = 14; 7 females) treated with GH + calcium gluconolactate and carbonate (1 g calcium/day per os). Auxological parameters, total bone mineral content (TBMC) and density (TBMD), leg BMC and BMD, lumbar BMD, fat mass (FM) and lean tissue mass (LTM), blood 25-hydroxyvitamin D (25-OHD), parathyroid hormone (PTH), osteocalcin (OC) and urinary N-terminal telopeptide of type I collagen (NTx) were determined at the start of therapy and after 1 and 2 years of treatment.

RESULTS

During the 2 years of the study, TBMC, TBMD, leg BMC and BMD (but not lumbar BMD) increased in both groups of patients, however after 2 years of treatment they were significantly higher in the calcium-supplemented group B than in group A (p < 0.05, for all parameters). At the start of therapy, in both groups of patients percentage FM was higher and total and leg LTM lower than in controls (p < 0.05 for each parameter). Thereafter, FM decreased and LTM increased and after 2 years they were both different from baseline (p < 0.05). After 2 years of treatment, leg BMC and BMD were more positively correlated with regional leg LTM in patients of group B (r = 0.834 and r = 0.827, respectively; p < 0.001) than in patients of group A (r = 0.617 and r = 0.637, respectively; p < 0.05). 25-OHD and PTH levels were in the normal range in all patients at the start and during treatment. OC levels were lower and urinary NTx levels higher in patients than in controls (p < 0.05 for both parameters), either at the start and after 1 year of treatment. After 2 years of treatment, OC levels were significantly higher than at the start of the study (p < 0.05) in both groups of patients, but they were higher in group B than in group A (p < 0.05); on the contrary, urinary Ntx levels were lower in group B than in group A (p < 0.05).

CONCLUSION

In GHD children, treated with GH, calcium supplementation improved bone mass; it may aid in reaching better peak bone mass and in protecting weight-bearing bones, usually completed in childhood to maximum levels, from risk of osteoporosis and fractures later in life.

Bone mineral density in relation to body mass index among young women: a prospective cohort study

AIM

To identify important predictors among lifestyle behaviours and physiological factors of bone mineral density (BMD) in relation to body mass index (BMI) among young women over a 2-year period. DESIGN, SAMPLE AND MEASUREMENTS: Data were collected in 1999 and 2001. Healthy young women (n=152) completed a questionnaire. BMD measurements were performed by DEXA in the calcaneus. The women were subdivided into three categories according to baseline BMI.

RESULTS

Baseline bodyweight explained 25% of the variability in BMD at follow-up in the BMI<19 category, and high physical activity seemed to hinder BMD development. In the BMI>24 category, a difference in time spent outdoors during winter between baseline and follow-up was the single most important factor for BMD levels. Overweight women with periods of amenorrhoea had lower BMD than overweight women without such periods.

CONCLUSIONS

Predictors and lifestyle behaviours associated with BMD are likely to be based on women of normal weight. BMI should be considered when advising on physical activity, since high physical activity seems to impair BMD development among underweight young women, possibly due to energy imbalance. Among overweight women, sleep satisfaction is the greatest predictor associated with BMD change and may indicate better bone formation conditions. Energy balance and sleep quality may be prerequisites of bone health and should be considered in prevention.

An adult physical activity scoring scheme: its evaluation and application

PURPOSE

The purpose of this paper was to describe the development and evaluation of an adult physical activity (PA) scoring scheme (SS).

METHODS

SS was based on the 2000 METs compendium and PA guidance. Scoring credit was assigned to moderate (3-6 METs) or vigorous (>6 METs) activities using a 100-point scale. A point designator for evaluation (80.01-100, good; 51.00-80, needs improvement; and <51, poor) was based on guidance to perform 30 min of moderate activity > or = 5 d x wk(-1) or 20 min of vigorous activity > or = 3 d x wk(-1). Activities were scored individually and summed for a final score. PA information was from the Behavioral Risk Surveillance Survey, 2000. Weighted data were analyzed using SAS. Sensitivity and specificity methods were used to evaluate the SS. Fifty-six PA met intensity criteria and were examined for frequency and duration.

RESULTS

Study included adults > or = 18 yr (N = 173,980). 71.4% of the men and 67.2% of the women reported moderate or vigorous activity, but only 13.1% of the men and 12.8% of the women received a good score. 48.9% of the men and 41% of the women needed improvement and 9.4% of the men and 13.4% of the women had a poor score. The sensitivity of identifying inactivity was 94 and 95% for inactive men and women, respectively; 92% for identifying both men and women needing improvement; and 79% for men and 90% for women with a poor score. The specificity of getting a good score was 57 and 60% for active men and women, respectively.

CONCLUSION

SS appropriately assigns scoring credit to moderate and vigorous activities. However, assumptions made for mixed moderate and vigorous activities may misclassify active individuals.

One year soy protein supplementation has positive effects on bone formation markers but not bone density in postmenopausal women

BACKGROUND

Although soy protein and its isoflavones have been reported to reduce the risk of osteoporosis in peri- and post-menopausal women, most of these studies are of short duration (i.e. six months). The objective of this study was to examine if one year consumption of soy-containing foods (providing 25 g protein and 60 mg isoflavones) exerts beneficial effects on bone in postmenopausal women.

METHODS

Eighty-seven eligible postmenopausal women were randomly assigned to consume soy or control foods daily for one year. Bone mineral density (BMD) and bone mineral content (BMC) of the whole body, lumbar (L1-L4), and total hip were measured using dual energy x-ray absorptiometry at baseline and after one year. Blood and urine markers of bone metabolism were also assessed.

RESULTS AND DISCUSSION

Sixty-two subjects completed the one-year long study. Whole body and lumbar BMD and BMC were significantly decreased in both the soy and control groups. However, there were no significant changes in total hip BMD and BMC irrespective of treatment. Both treatments positively affected markers of bone formation as indicated by increased serum bone-specific alkaline phosphatase (BSAP) activity, insulin-like growth factor-I (IGF-I), and osteocalcin (BSAP: 27.8 and 25.8%, IGF-I: 12.8 and 26.3%, osteocalcin: 95.2 and 103.4% for control and soy groups, respectively). Neither of the protein supplements had any effect on urinary deoxypyridinoline excretion, a marker of bone resorption.

CONCLUSION

Our findings suggest that although one year supplementation of 25 g protein per se positively modulated markers of bone formation, this amount of protein was unable to prevent lumbar and whole body bone loss in postmenopausal women.

Long-term implementation of the CATCH physical education program

To test the effectiveness of the Child and Adolescent Trial for Cardiovascular Health (CATCH) program, a randomized trial was conducted in 96 elementary schools in four regions of the United States. Results from the original trial indicated a significant positive effect on the delivery of physical education (PE). All 56 former intervention schools (FI), 20 randomly selected former control schools (FC), and 12 newly selected unexposed control schools (UC) were assessed 5 years postintervention. Results indicate a strong secular trend of increasing moderate to vigorous physical activity (MVPA) in PE classes among both FC and UC schools. The FI schools surpassed the Healthy People 2010 goal for MVPA during PE lesson time (i.e., 50%), whereas the FC and UC schools came close to it. Barriers to implementing CATCH PE included insufficient training and lower importance of PE compared to other academic areas and indicate the need for in-service training.

Bone mineral density and the subsequent risk of cancer in the NHANES I follow-up cohort

Backgroud

Bone mineral density (BMD) is a marker of long-term estrogen exposure. BMD measurement has been used in this context to investigate the association of estrogen with breast cancer risk in three cohorts. In order to assess further BMD as a predictor of estrogen related cancer risk, the association of BMD with colorectal and corpus uteri cancer was investigated in the NHANES I Epidemiologic Followup Study (NHEFS) cohort along with breast cancer and prostate cancer.

Methods

Participants were members of the NHEFS cohort who had BMD measurement in 1974–1975. Age, race, and BMI adjusted rate ratios and 95% confidence intervals were calculated for incidence of cancers of the corpus uterus, breast, colorectum, prostate, and of osteoporosis and hip fracture related to baseline BMD.

Results

Data were available for 6046 individuals. One hundred cases of breast cancer, 94 prostate cancers, 115 colorectal cancers, 29 uterine cancers, 110 cases of hip fracture and 103 cases of osteoporosis were reported between 1974 and 1993. Hip fracture and osteoporosis were both significantly inversely associated with BMD. Uterine cancer was positively associated (p = 0.005, test for linear trend) and colorectal cancer negatively associated (p = 0.03) with BMD. No association was found between elevated BMD and incidence of breast cancer (p = 0.74) or prostate cancer (p = 0.37) in the overall cohort, although a weak association was seen between BMD and subsequent breast cancer incidence when BMD was measured in post-menopausal women (p = 0.04).

Conclusion

The findings related to cancers of the uterus and colorectum as well as the weak association of BMD with breast cancer strengthen the use of BMD as a marker of estrogen exposure and cancer risk.

Total physical activity in relation to age, body mass, health and other factors in a cohort of Swedish men

BACKGROUND

Despite a large public health interest in physical activity and its role in obesity and other chronic diseases, only a few reports to date have addressed total levels of physical activity in relation to age, body mass, health and other lifestyle factors.

OBJECTIVE

To investigate whether levels of total physical activity among men are associated with age, body mass, self-rated health and other lifestyle factors in a cross-sectional setting.

METHODS

In a population-based cohort of 33 466 men aged 45-79 y in central Sweden, we collected information about physical activity through a self-administered questionnaire. Level of total physical activity was assessed quantitatively based on six questions on different activities: work/occupation, housework, walking/bicycling, exercise, inactive leisure time and sleeping. The physical activity levels were measured as metabolic equivalents, MET-h/day. The relation between age, body mass index, smoking, education, marital status and self-rated health, and total physical activity was studied in a cross-sectional analysis, using multivariate regression.

RESULTS

Total daily physical activity was decreasing systematically between age 45 and 79 (-4.1%, 95% CI -4.6, -3.6). Obese men reported -2.6% (95% CI -3.0, -2.1) lower physical activity than normal weight men. Those with high education had -7.0% (95%CI -7.3, -6.7) lower total physical activity than those with elementary school. Men with self-rated poor health had -11.3% (95%CI -12.1, -10.6) lower physical activity than those reporting very good health. The cross-sectionally observed decrease with age was greatest among obese men (-8.7%), current smokers (-7.9%), low-educated men (-5.6%) and those with poor health (-9.8%); the subgroups with very good health reported almost the same level of total physical activity (-0.6%) for age 74-79 as for age 45-49.

CONCLUSIONS

The observed decreasing levels of total physical activity with age to large degree depend on health status and other factors. The characterization of subjects with low total physical activity levels is of importance for understanding observed worldwide trends in increasing prevalence of obesity. The better understanding of these phenomena might also facilitate a better planning of public health interventions with messages specifically adjusted for subgroups of population with lower physical activity.

Association of lean tissue and fat mass with bone mineral content in children and adolescents

OBJECTIVES

There has been uncertainty in the adult body composition literature about whether fat mass (FM) or fat free mass is a better predictor of bone mineral content and bone mineral density. This issue has recently also been raised in the pediatric literature. Based on suggested skeletal muscle-bone relationships, this study tested the hypothesis that in children and adolescents lean tissue mass (LTM) is a better predictor of total bone mineral content (TBMC) than is FM.

RESEARCH METHODS AND PROCEDURES

Subjects were 133 Italian children and adolescents, 5 to 17 years of age, undergoing a routine medical screen. FM (kilograms), LTM (kilograms), and TBMC (kilograms) were measured by DXA. Multiple regression analyses tested the independent association of FM and LTM with bone mineral content.

RESULTS

Regression analyses, adjusting for pubertal status and other covariates, showed that FM and LTM were independently associated with TBMC. These associations were similar for boys and girls. TBMC was more strongly associated with LTM than FM.

DISCUSSION

These observations support the hypothesis that in children and adolescents a close association exists between LTM, a measure of skeletal muscle, and skeletal characteristics.

Dried plums improve indices of bone formation in postmenopausal women

Menopause drastically increases the risk of osteoporosis. Aside from drug therapy, lifestyle and nutritional factors play an important role in the maintenance of skeletal health. Our recent findings suggest that dried plums, a rich source of phenolic and flavonoid compounds, are highly effective in modulating bone mass in an ovarian hormone-deficient rat model of osteoporosis. The objective of this study was to examine whether the addition of dried plums to the diets of postmenopausal women positively influences markers of bone turnover. Fifty-eight postmenopausal women not on hormone replacement therapy (HRT) were randomly assigned to consume either 100 g dried plums or 75 g dried apples daily for 3 months. Both dried fruit regimens provided similar amount of calories, fat, carbohydrate, and fiber. Serum and urinary biochemical markers of bone status were assessed before and after treatment. In comparison with corresponding baseline values, only dried plums significantly increased serum levels of insulin-like growth factor-I (IGF-I) and bone-specific alkaline phosphatase (BSAP) activity. Higher levels of both serum IGF-I and BSAP are associated with greater rates of bone formation. Serum and urinary markers of bone resorption, however, were not affected by either dietary regimen. The results of this study suggest that dried plums may exert positive effects on bone in postmenopausal women. Longer duration studies are needed to confirm the beneficial effects of dried plum on bone mineral density (BMD) and the skeletal health of postmenopausal women.

Effects of an osteoporosis prevention program incorporating tailored educational materials

PURPOSE

To evaluate the effects of two interventions on calcium intake and exercise and assess whether intervention effects varied as a function of participants' stage of change.

DESIGN

The study used a 2 by 2 factorial research design. Baseline, 3-, 6-, and 12-month follow-up data were collected.

SETTING

Twelve counties in western North Carolina.

SUBJECTS

Of 714 women recruited, 547 (76.6%) completed all data collection procedures.

INTERVENTION

One intervention, conducted at the individual level, compared the effects of tailored vs. nontailored educational materials. The tailored educational intervention was delivered via two packets of written materials and one telephone counseling session. The written materials and counseling session were tailored according to participants' current calcium intake and exercise level, perceived adequacy of these behaviors, stage of change, behavioral goals, and perceived barriers to change. A community-based intervention was also evaluated. This intervention, implemented in 6 of the 12 counties, included establishing an Osteoporosis Resource Center, conducting a workshop on osteoporosis prevention, and offering free bone density screening.

MEASURES

Outcome measures were calcium intake and exercise level. Stage of change was assessed as a moderating variable.

RESULTS

Irrespective of intervention group, among women not consuming adequate calcium at baseline, intake increased an average of about 500 mg/d over the course of the study. Changes involving exercise were more modest. Repeated measures regression analyses were used to evaluate intervention effects. The effect of the tailored educational intervention varied, in appropriate ways, among women in different stages of change at baseline (F2,527 = 6.37, p < .002). Among women in the Engaged stage, the tailored intervention was associated with a greater increase in calcium intake. In contrast, among women who were obtaining adequate calcium at baseline (i.e., Action stage), the tailored intervention appeared to forestall inappropriate increases in calcium intake. The community-based intervention had no consistent effects on calcium intake, either alone, or in combination with the tailored intervention. Finally, neither intervention had an effect on exercise, either alone or in combination.

CONCLUSIONS

Limited support for the superiority of tailored vs. nontailored educational interventions was found. The differential effects observed could be due to the telephone counseling received by women in the Tailored Education Group, however.

Validity and reproducibility of self-reported total physical activity—differences by relative weight

OBJECTIVE

Physical activity is hypothesized to reduce the risk of obesity and several other chronic diseases and enhance longevity. However, most of the questionnaires used measure only part of total physical activity, occupational and/or leisure-time activity, which might lead to misclassification of total physical activity level and to dilution of risk estimates. We evaluated the validity and reproducibility of a short self-administered physical activity questionnaire, intended to measure long-term total daily 24 h physical activity.

METHOD

The questionnaire included questions on level of physical activity at work, hours per day of walking/bicycling, home/household work, leisure-time activity/inactivity and sleeping and was sent twice during one year (winter/spring and late summer). Two 7-day activity records, performed 6 months apart, were used as the reference method. One-hundred and eleven men, aged 44-78, completed the questionnaire and one or two activity records. The physical activity levels were measured as metabolic equivalents (MET)xh/day.

RESULTS

Spearman correlation coefficient between total daily activity score estimated from the first questionnaire and the records (validity) was 0.56 (deattenuated) and between the first and the second questionnaire (reproducibility) 0.65. Significantly higher validity correlations were observed in men with self-reported body mass index below 26 kg/m(2) than in heavier men (r=0.73 vs r=0.39).

CONCLUSIONS

This study indicates that the average total daily physical activity scores can be estimated satisfactorily in men using this simple self-administered questionnaire.