Relationships between leisure-time physical activity, obesity and disability in elderly men

BACKGROUND AND AIMS: Relationships have already been shown between leisure-time physical activity, obesity and body composition in young adults. However, this association needs to be confirmed in the elderly. The aim of this study was to investigate the relationship between leisure-time physical activity, obesity, preservation of muscle mass and disability in elderly men. METHODS: Cross-sectional analysis of a sample of 85 community-dwelling men, 68 to 79 years of age. Body mass index (BMI) was used to quantify obesity. Body composition was evaluated using Dual Energy X-ray Absorptiometry. Disability was measured using a modified version of the Activities of Daily Living scale. Leisure-time physical activity was evaluated by a validated self-administered questionnaire. RESULTS: A negative relation between obesity and weekly walking was observed. Walking less than 30 minutes per day was associated with a 2.7 greater probability of being obese (95% CI 1.1-6.7). High-intensity exercise, such as brisk walking or gardening, was inversely correlated with body fat (R = -0.296, p < 0.01) and directly correlated with appendicular skeletal mass (R = 0.238, p < 0.05). The prevalence of disability was the highest (58%) among overweight elderly subjects at the lowest tertile of exercise. Multiple logistic regression selected BMI as a positive predictor and high-intensity exercise as a negative predictor of disability. CONCLUSIONS: Our study shows that, in elderly men, leisure-time physical activity is inversely associated with body fat, BMI, and reported disability, but positively associated with appendicular fat-free mass. The highest prevalence of reported disability was observed in sedentary subjects with BMI higher than 25 kg/m2.     

Work-related repetitive strain injury and leisure-time physical activity

OBJECTIVE: To investigate the relationship between leisure-time physical activity and work-related repetitive strain injury (RSI), adjusted for sociodemographic characteristics and work-related physical and stress factors. METHODS: The data source was the 2003 Canadian Community Health Survey, a national cross-sectional survey of 134,072 respondents. The analysis was limited to a sample of the survey population reporting full-time work during the past 12 months (n = 58,622). The outcome of interest was work-related RSI of the upper body. Multiple logistic regression was used to examine the relationship between the outcome and leisure-time physical activity level, adjusted for sociodemographic, health, and occupational characteristics. The potential effect of leisure-time physical activity with a high upper-body load was investigated in a secondary analysis. RESULTS: The prevalence of upper-body work-related RSI was 5.9% in the Canadian population in 2003. An active lifestyle during leisure time was associated with a lower prevalence of work-related upper-body RSI (odds ratio 0.84, 99% confidence interval 0.75-0.95), after adjustment for work physical demands and other covariates. Female sex, obesity, smoking, age, work-related stress, and work physical demands were associated with RSI. In the secondary analysis, we did not find that participating in leisure-time activities with a high upper-body load was a risk factor for RSI. CONCLUSION: Our study results indicate that being physically active during leisure time is associated with a decreased risk of upper-body occupational RSI, adding another potential health benefit to participation in leisure-time physical activity.     

Combined effect of physical activity and leisure time sitting on long-term risk of incident obesity and metabolic risk factor clustering

Aims/hypothesis

Our study aimed to investigate the combined effects of moderate-to-vigorous physical activity and leisure time sitting on the long-term risk of obesity and clustering of metabolic risk factors.

Methods

The duration of moderate and vigorous physical activity and of leisure time sitting was assessed by questionnaire between 1997 and 1999 among 3,670 participants from the Whitehall II cohort study (73% male; mean age 56 years). Multivariable-adjusted logistic regression models examined associations of physical activity and leisure time sitting tertiles with odds of incident obesity (BMI?≥?30 kg/m²) and incident metabolic risk factor clustering (two or more of the following: low HDL-cholesterol, high triacylglycerol, hypertension, hyperglycaemia, insulin resistance) at 5 and 10 year follow-ups.

Results

Physical activity, but not leisure time sitting, was associated with incident obesity. The lowest odds of incident obesity after 5 years were observed for individuals reporting both high physical activity and low leisure time sitting (OR?=?0.26; 95% CI 0.11, 0.64), with weaker effects after 10 years. Compared with individuals in the low physical activity/high leisure time sitting group, those with intermediate levels of both physical activity and leisure time sitting had lower odds of incident metabolic risk factor clustering after 5 years (OR 0.53; 95% CI 0.36, 0.78), with similar odds after 10 years.

Conclusions/interpretation

Both high levels of physical activity and low levels of leisure time sitting may be required to substantially reduce the risk of obesity. Associations with developing metabolic risk factor clustering were less clear.     

Sitting time and socio-economic differences in overweight and obesity

OBJECTIVES: To examine (1) the inter-relationships between socio-economic status (SES), physical activity, three different domains of sitting time (weekday, weekend day and leisure-time sitting), and being overweight or obese (body mass index>/=25 kg/m(2)); and (2) the potential mediation effects of sitting time in the relationship between socio-economic factors and being overweight or obese in working Australian adults. DESIGN: Observational epidemiological study. SUBJECTS: One thousand forty eight working adults. Using a multistage sampling design on neighbourhood SES, participants were from high and low SES neighbourhoods of an Australian capital city. MEASUREMENTS: Neighbourhood SES was assessed using census data; individual SES was based on self-reported educational attainment and household income. There were three sitting time variables: sitting time on weekdays, weekend days and in leisure time. Overweight and obesity were determined using self-reported body weight and height. RESULTS: Gender, age, neighbourhood SES, education, working hours and physical activity were independently associated with weekday, weekend day and leisure-related sitting time. With the exception of education and working hours, these variables were also independently associated with being overweight or obese. Leisure-time sitting was found to be a mediator in the relationships between gender, education and being overweight or obese. CONCLUSION: Strategies to promote less sitting in leisure time are required to combat overweight and obesity in Australian adults, especially among those from low SES neighbourhoods, and among those with high levels of education and income who work long hours.     

Trends in overweight and obesity from 1985 to 2002 in Göteborg, West Sweden

OBJECTIVE: To study secular trends in overweight and selected correlates in men and women in G?teborg, Sweden. DESIGN: Cross-sequential population-based surveys. SUBJECTS: A total of 2931 female and 2691 male subjects aged 25-64 y participated in WHO MONICA surveys (1985, 1990, 1995) and the INTERGENE study (2002). MEASUREMENTS: Body mass index (BMI), waist-to-hip ratio (WHR), prevalence of overweight (BMI> or =25 kg/m(2)), and obesity (BMI> or =30 kg/m(2)). RESULTS: Mean body weight increased by 3.3 kg for women and 5 kg for men, with a significant upward trend for BMI in men but not women over the 17-y observation period. The prevalence of overweight and obesity increased significantly in both sexes over the period. The largest increase was observed in men, and in women aged 25-34 y. In 2002, the prevalence of overweight was 38% in women and 58% in men, and the prevalence of obesity was 11% in women and 15% in men. No significant secular trends were observed for WHR, but there was an upward trend in prevalence of WHR>0.85 in women. A decreased prevalence of smoking in both sexes was observed together with an increase in reported leisure time physical activity. No significant secular trends were observed in rates of self-reported diabetes, although the risk of diabetes attributable to obesity was 24%. CONCLUSION: The results indicate that 25-64-y-olds in the recent survey were more overweight and obese than earlier studied MONICA participants. The increase in BMI was more pronounced in men while abdominal obesity increased principally in women. Although obesity and overweight are clearly important risk factors for type 2 diabetes, the number of diabetics remains low and any secular increase is not yet apparent.     

Physical activity, leisure habits and obesity in first-grade children.

BACKGROUND: Overweight and obesity are already on the rise in early childhood years. The relationships between genetic factors, malnutrition and physical inactivity are the underlying mechanisms. In this study, we examine the association between body indices, motor abilities and active (sport) and passive (television/computer) leisure time activities in a cohort of first-grade pupils. METHODS: The study group consisted of 344 children (51.5% male, 48.5% female). They were 6.8+/-0.4 years old, height was 123.9+/-4.9 cm, weight 24.8+/-5.0 kg, body mass index (BMI) 16.1+/-2.3 kg/m. After determination of the anthropometric data, a fitness test was performed in order to determine motor abilities. Parents were questioned about their children's leisure time activities, using a standardized questionnaire. Differences between BMI groups were evaluated using multivariate ANCOVA, adjusted for gender and age. RESULTS: Based on German BMI references, overweight and obesity were found in 12% of the children. They had poorer results with respect to endurance (P<0.001), leg strength (P=0.002), co-ordination and balance (P=0.045) and spent more leisure time in watching television and at the computer (each P<0.001). No differences were found between their active leisure habits such as club sports. DISCUSSION: Our examinations with first-grade children show no differences in active leisure habits between obese children and their counterparts, although the former had poorer results in motor abilities, but they spend more time on sedentary leisure habits like audiovisual media. A possible explanation is their fewer regular daily activities.     

Obesity in Canada: where and how many?

CONTEXT: Obesity rates are rising sharply among all industrialized countries; the situation seems to be worse in English speaking countries. Taking into account genetic predisposition, excess of caloric intake combined with low energy expenditure will usually result in obesity. OBJECTIVES: To describe and compare regional obesity rates across Canada and assess the ecological relationship between regional rates of obesity, low level of leisure-time physical activity, and low fruit and vegetable consumption. DESIGN: Cross-sectional population-based analysis from the 2003 Canadian Community Health Survey. MEASURES AND DATA ANALYSES: Canadian population distributions of body mass index (BMI), leisure-time physical activity and daily fruit and vegetable consumption were obtained from Statistics Canada. All these measures were based on the respondent's self-reported answers to a computer-assisted personal or telephone interview. Obesity rates (BMI> or =30), rates of low level of leisure-time physical activity (less than 1.5 kcal of energy expenditure per day), and rates of low fruit and vegetable consumption (less than five times a day) for the 106 Canadian Health regions were mapped to illustrate their geographical distribution. Cartograms were used in addition to traditional mapping to take into account the differences in population density between these small areas. RESULTS: In 2003, 15.2% of Canadian individuals aged 20 years and older were considered obese. The rates of obesity varied substantially between the 106 Canadian health regions: from 6.2% in Vancouver to 47.5% in aboriginal population area. At the health region level, low leisure-time physical activity and low fruit and vegetable consumption are both good predictors of obesity (odds ratio of 9.2 and positive predictive value of 93% when considered simultaneously). CONCLUSION: There is a strong gradient in obesity prevalence between Canadian health regions. At the regional level, high rates of low level of physical activity, and high rates of low fruit and vegetable consumption were both found good predictors of high rates of obesity.     

Relief of cardiorespiratory symptoms and increased physical activity after surgically induced weight loss: results from the Swedish Obese Subjects study

BACKGROUND: Obese people frequently suffer from shortness of breath and chest discomfort on exertion, and they often have a sedentary lifestyle. In the present study of patients with severe obesity, we investigated the effects of surgically induced weight loss on cardiorespiratory symptoms and leisure-time physical activity. METHODS: The Swedish Obese Subjects study is an ongoing intervention trial of obesity consisting of 1 surgically treated group and 1 matched control group. Information on smoking habits, hypertension, diabetes, and sleep apnea was obtained from 1210 surgical cases and 1099 controls who were observed for 2 years. Patients were also asked about symptoms of breathlessness and chest pain and their levels of leisure-time physical activity. RESULTS: The surgically treated group displayed a mean weight loss of 28 kg (23%) compared with the control group in which the average weight remained unchanged (P<.001). The rates of hypertension, diabetes, and apneas during sleep decreased in surgical cases compared with controls (P<.001), while smoking habits remained largely the same. The surgical group also displayed highly significant improvements in dyspnea and chest pain and increases in physical activity compared with the control group (P<.001). The odds ratio for self-reported breathlessness, chest discomfort, or sedentary behavior after 2 years decreased progressively with the degree of weight loss. Furthermore, patients who recovered from apneas during sleep reduced their odds of having dyspnea and chest discomfort at follow-up, independent of changes in weight. CONCLUSIONS: Surgically induced weight loss in patients with severe obesity is associated with a marked relief in symptoms of dyspnea and chest pain and promotes increased leisure-time physical activity. Sleep-disordered breathing may be involved in the pathophysiology of breathlessness and chest discomfort in obese subjects.     

Determinants of geographical variations in body mass index (BMI) and obesity in Spain.

OBJECTIVE: To identify the factors associated with geographic variations in Body Mass Index (BMI) and obesity in Spain. DESIGN: Cross-sectional, ecological analysis using data on illiteracy rate (per 1000 population), energy intake (kcal/person/d), sedentary population (%), smoking population (%), alcohol consumption (g/person/d), and percentage of population aged 65 y or over, for Spain's 50 provinces. SUBJECTS: Non-institutionalized population aged 16y or over. MEASUREMENTS: Median BMI and percentage of population with obesity, defined as BMI > 30 kg/m2. RESULTS: There was a clear geographical pattern, with some areas in the south and north-west of the country registering the highest BMI and prevalence of obesity and a north-south pattern on illiteracy per 1000 population. Multivariate regression analysis showed that illiteracy, sedentary lifestyle and energy intake explain 35% and 14% of the variation in BMI and obesity, respectively. Illiteracy proved to be the variable most associated with both BMI (regression coefficient (beta = 0.01; P = 0.005) and obesity (beta = 0.05; P = 0.013). Sedentary lifestyle showed a statistically significant relationship with BMI (beta = 0.01; P = 0.03), but not with obesity (beta = 0.03; P = 0.581). Energy intake exhibited a relationship with BMI (beta < 0.01 P = 0.03) that lost statistical significance when adjusted for age. CONCLUSION: Geographical variations in BMI in Spain are partly explained by illiteracy, sedentary lifestyle and, to a lesser extent, energy intake, whereas regional variations in obesity are related only to the educational level of the population.     

Use of information and communication technology and prevalence of overweight and obesity among adolescents

BACKGROUND: The prevalence of overweight and obesity has increased among children and adolescents, as well as among adults, and television viewing has been suggested as one cause. Playing digital games (video, computer and console games), or using computer may be other sedentary behaviors related to the development of overweight and obesity. OBJECTIVE: To study the relationships of times spent on viewing television, playing digital games and using computer to overweight among Finnish adolescents. DESIGN: Mailed cross-sectional survey. SUBJECTS: Nationally representative samples of 14-, 16-, and 18-y-old (N=6515, response rate 70%) in 2001. METHODS: Overweight and obesity were assessed by body mass index (BMI). The respondents reported times spent daily on viewing television, playing digital games (video, computer and console games) and using computer (for e-mail, writing and surfing). Data on timing of biological maturation, intensity of weekly physical activity and family's socio economic status were taken into account in the statistical analyses. RESULTS: Increased times spent on viewing television and using computer were associated with increased prevalence of overweight (obesity inclusive) among girls: compared to girls viewing television <1 h daily, the adjusted odds ratio (OR) for being overweight was 1.4 when spending 1-3 h, and 2.0 when spending > or =4 h daily on viewing television. In girls using computer > or =1 h daily, the OR for being overweight was 1.5 compared to girls using computer <1 h daily. The results were similar in boys, although not statistically significant. Time spent on playing digital games was not associated with overweight. CONCLUSION: Overweight was associated with using information and communication technology (ICT), but only with certain forms of ICT. Increased use of ICT may be one factor explaining the increased prevalence of overweight and obesity at the population level, at least in girls. Playing digital games was not related to overweight, perhaps by virtue of game playing being less sedentary or related to a different lifestyle than viewing television and using computer.     

Sitting time and work patterns as indicators of overweight and obesity in Australian adults

BACKGROUND: Increasing levels of physical inactivity and sedentariness are contributing to the current overweight and obesity epidemic. In this paper, the findings of two recent studies are used to explore the relationships between sitting time (in transport, work and leisure), physical activity and body mass index (BMI) in two contrasting samples of adult Australians. METHODS: Data on sitting time, physical activity, BMI and a number of demographic characteristics were compared for participants in two studies-529 women who were participants in a preschool health promotion project ('mothers'), and 185 men and women who were involved in a workplace pedometer study ('workers'). Relationships between age, number of children, physical activity, sitting time, BMI, gender and work patterns were explored. Logistic regression was used to predict the likelihood of being overweight or obese, among participants with different physical activity, sitting time and work patterns. RESULTS: The total reported time spent sitting per day (across all domains) was almost 6 h less among the mothers than the workers (P<0.001), and compared with the mothers, a significantly greater proportion of the workers was classified as overweight or obese (BMI > or =25 kg/m(2)). Univariate analysis found that, compared with men in full-time work, women who worked full-time (OR=0.42, CI: 0.24-0.74), part-time (OR=0.35, CI: 0.20-0.59) or in full-time home duties (OR=0.51, CI: 0.29-0.88) were about half as likely to be overweight or obese. Participants who reported high daily levels of sitting (> or =7.4 h) were also significantly more likely than those who reported 'low' levels (<4.7 h/day) to be overweight or obese (OR=1.68, CI: 1.16-2.42). Multivariate analysis (including physical activity, work patterns and sitting time) confirmed that full-time and part-time working women (but not 'home duties' women) were less likely to report BMI > or =25 kg/m(2) than full-time working men (full-time: OR=0.44, CI: 0.25-0.78; part-time: OR=0.45, CI: 0.24-0.86), but the OR for BMI > or =25 among those in the high sitting category was attenuated (OR=1.61, CI 0.96-2.71). CONCLUSIONS: The findings suggest a need for inclusion of measures of both activity and inactivity in future studies, so that the complex relationships between these behavioural determinants of BMI can be clarified.     

Factors associated to lifestyle and risk of adult onset asthma

BACKGROUND: Asthma prevalence has been increasing especially in developed countries. The change seems to be associated with changes in lifestyle. We have made a prospective study to assess the effect of lifestyle factors, including smoking, educational level, physical activity and obesity on adult onset asthma. METHODS: A population of 10,597 adult twins, initially free of asthma was followed for 9 years. The main outcome measure was questionnaire-based report of physician diagnosed asthma. Logistic regression was used to estimate the risk of asthma predicted by lifestyle factors, with adjustment for atopy and respiratory symptoms. RESULTS: Obesity at baseline increased asthma risk (multivariable adjusted OR = 3.00, 95% CI: 1.64-5.50 for those with BMI > or = 30 compared to those with normal weight BMI: 20-24.99). Taller height was associated to lower asthma incidence. Leisure time physical activity had a slightly protective effect on asthma risk among men (P for trend = 0.037) while smoking and education did not have significant effects on the risk of adult onset asthma. CONCLUSIONS: Obesity was associated to the risk of adult onset asthma, while short height and low leisure time physical activity can be considered as other potential risk factors.     

Sedentary behaviour,physical activity and dietary patterns are independently associated with the metabolic syndrome

AimThis study assessed the independent relationships of daily sitting time, levels of work and leisure-time physical activity (PA), and dietary patterns of patients with the metabolic syndrome (MetS).MethodsThis population-based, cross-sectional study included 3090 French subjects aged 35–64 years. Daily time spent sitting and PA levels were assessed by an interview-administered questionnaire, while dietary patterns were identified using the factorial method of principal component analysis. Independent associations of lifestyle behaviours with the MetS were assessed by multivariable logistic-regression models adjusted for age, centre, educational level, smoking status, total calorie intake, heart rate and menopausal status.ResultsThe multivariable-adjusted ORs [95% CI] for MetS in the fourth quartile of sitting time and leisure-time PA were 1.65 [1.11–2.44] (P for trend < 0.01) and 0.58 [0.40–0.84] (P for trend < 0.001), respectively, for men, and 2.35 [1.41–3.92] (P for trend < 0.01) and 0.52 [0.33–0.82] (P for trend < 0.01), respectively, for women. Work PA was not favourably related to the MetS, particularly in women. An ‘energy-dense’ dietary pattern was independently associated with higher ORs for the MetS in both genders. However, accounting for body mass index (BMI) weakened the associations, which otherwise remained significant for leisure-time PA and the energy-dense dietary pattern in men, suggesting that BMI may be a potential mediator of these relationships.ConclusionThis study demonstrated a dose–response association between sitting time, an energy-dense dietary pattern and the MetS, together with a graded inverse association between leisure-time PA and the MetS. In addition to the usual advice for PA and healthy eating, limiting the amount of time spent sitting should also be promoted through public-health initiatives.     

Overweight and obesity among schoolchildren in Sana'a City, Yemen

AIM: To estimate the prevalence of overweight and obesity among schoolchildren in Sana'a City (Yemen) and to examine the association with lifestyle and some socioeconomic factors. METHODS: A cross-sectional study was done in public and private schools in Sana'a City during 2002-2003. We selected 1,253 students by the multistage random sampling technique. Weights and heights were measured to calculate body mass index (BMI = weight/height2). Data about age, sex, education level of the parents, food consumption and lifestyle was also collected. RESULTS: The mean age of the children was 12.6 +/- 2 years. Overweight was 6.2% and obesity was 1.8%. The prevalence of overweight and obesity was higher among private schoolchildren (p<000), females (p = 0.002), children with a sedentary lifestyle (p = 0.001) and children with a family history of obesity (p = 0.013). Also there is a positive association of overweight/obesity with the education level of the parents (p = 0.013 for the father and p = 0.19 for the mother) and consumption of unhealthy foods. CONCLUSION: Prevalence of overweight and obesity is low and positively associated with the education level of the father, private schooling, sedentary lifestyle, and with students who took unhealthy meals.     

Too much sitting - A health hazard

In contemporary society, prolonged sitting has been engineered into our lives across many settings, including transportation, the workplace, and the home. There is new evidence that too much sitting (also known as sedentary behavior - which involves very low energy expenditure, such as television viewing and desk-bound work) is adversely associated with health outcomes, including cardio-metabolic risk biomarkers, type 2 diabetes and premature mortality. Importantly, these detrimental associations remain even after accounting for time spent in leisure time physical activity. We describe recent evidence from epidemiological and experimental studies that makes a persuasive case that too much sitting should now be considered an important stand-alone component of the physical activity and health equation, particularly in relation to diabetes and cardiovascular risk. We highlight directions for further research and consider some of the practical implications of focusing on too much sitting as a modifiable health risk.     

Prolonged sitting may increase diabetes risk in physically inactive individuals: an 11 year follow-up of the HUNT Study,Norway

Aims/hypothesis

We examined the association between sitting time and diabetes incidence, overall and by strata of leisure-time physical activity and BMI.

Methods

We followed 28,051 adult participants of the Nord-Trøndelag Health Study (the HUNT Study), a population-based study, for diabetes incidence from 1995–1997 to 2006–2008 and estimated HRs of any diabetes by categories of self-reported total daily sitting time at baseline.

Results

Of 28,051 participants, 1253 (4.5%) developed diabetes during 11 years of follow-up. Overall, sitting ≥8 h/day was associated with a 17% (95% CI 2, 34) higher risk of developing diabetes compared with sitting ≤4 h/day, adjusted for age, sex and education. However, the association was attenuated to a non-significant 9% (95% CI ?5, 26) increase in risk after adjustment for leisure-time physical activity and BMI. The association between sitting time and diabetes risk differed by leisure-time physical activity (p _Interaction?=?0.01). Among participants with low leisure-time physical activity (≤2 h light activity per week and no vigorous activity), sitting 5–7 h/day and ≥8 h/day were associated with a 26% (95% CI 2, 57) and 30% (95% CI 5, 61) higher risk of diabetes, respectively, compared with sitting ≤4 h/day. There was no corresponding association among participants with high leisure-time physical activity (≥3 h light activity or >0 h vigorous activity per week). There was no statistical evidence that the association between sitting time and diabetes risk differed by obesity (p _Interaction?=?0.65).

Conclusions/interpretation

Our findings suggest that total sitting time has little association with diabetes risk in the population as a whole, but prolonged sitting may contribute to an increased diabetes risk among physically inactive people.

     

Family history of diabetes identifies a group at increased risk for the metabolic consequences of obesity and physical inactivity in EPIC-Norfolk: a population-based study. The European Prospective Investigation into Cancer

OBJECTIVE: To investigate the interaction of a family history of diabetes with obesity and physical inactivity on diabetes prevalence in middle-aged and elderly men and women. DESIGN: A cross-sectional population-based study. SUBJECTS: 2,912 men and 3,561 women, aged 45-74y. MEASUREMENTS: Body mass index (BMI), HbA1C, self-administered questionnaire including questions on occupational physical activity and personal and family history of diabetes as part of the Norfolk arm of the European Prospective Investigation into Cancer (EPIC-Norfolk). RESULTS: The prevalence of diabetes increased in a dose-response relationship with increasing BMI. There was an interaction between family history and obesity on diabetes risk in subjects with a BMI of greater than 27.5kg/m2 (P= 0.049). Crude prevalence in individuals without a family history and BMI of 22.5-24.9 kg/m2 was 2.2% compared to 33.3% in those with a family history and BMI over 35 kg/m2. Thirty-eight percent of the excess risk of diabetes in people with a family history could be avoided if their BMI did not exceed 30 kg/m2. Individuals who reported sedentary occupations were at greater risk of diabetes compared to those reporting more active occupations. There was a synergistic effect of family history and self-reported occupational physical activity on diabetes risk. CONCLUSION: Individuals with a family history of diabetes are at increased risk for the metabolic consequences of obesity and form an easily identifiable group who may benefit from targeted intervention to prevent the development of obesity through increased physical activity.     

BMI from 3-6 y of age is predicted by TV viewing and physical activity, not diet

OBJECTIVE: To investigate whether, diet, physical activity, sedentary behavior or television (TV) viewing predicted body mass index (BMI) among 3-7-y-old children. DESIGN: A triethnic cohort of 3-4-y-old children was followed for 3 y from 1986 to 1989. MEASUREMENTS: BMI was assessed at the beginning and end of each measurement year. Heart rate monitoring and observation were used to assess physical activity. Diet (calories, % calories from fat and carbohydrate), sedentary behavior and TV viewing were assessed by direct observation in each year. A repeated measures regression analysis with year as a factor and BMI at the end of each year as dependent variables was run. Nonsignificant variables were removed in a stepwise backward deletion process and significant interactions graphed. RESULTS: The interactions between minutes of TV viewing per hour and study year and minutes of physical activity per hour and study year were significant (P<0.05). There were also significant main effects for TV viewing, physical activity and BMI from the beginning of the study. The model accounted for 65% of the variance in BMI across the three study years. Plotting the significant interactions demonstrated that physical activity was positively associated with BMI in year 1, and negatively associated in years 2 and 3 with a stronger negative relationship in year 3 than 2. TV viewing became positively associated with BMI during the third study year. CONCLUSION: Physical activity and TV viewing were the only significant predictors (other than baseline BMI) of BMI among a triethnic cohort of 3-4-y-old children followed for 3 y with both physical activity (negatively associated) and TV viewing (positively associated) becoming stronger predictors as the children aged. It appears that 6 or 7 y is a critical age when TV viewing and physical activity may affect BMI. Therefore, focusing on reducing time spent watching television and increasing time spent in physical activity may be successful means of preventing obesity among this age group.     

Obesity,sedentary lifestyle,and exhaled nitric oxide in an early adolescent cohort

Fractional exhaled nitric oxide (FeNO) is a marker of airway inflammation that is well‐characterized in allergic disease states. However, FeNO is also involved in nonallergic inflammatory and pulmonary vascular mechanisms or responses to environmental stimuli. We sought to determine the extent to which obesity or sedentary lifestyle is associated with FeNO in adolescents not selected on the basis of allergic disease. In Project Viva, a prebirth cohort study, we measured body mass index (BMI), skinfold thicknesses, waist circumference, body fat, hours watching television, hours of physical activity, and heart rate after exercise among 929 adolescents (median age, 12.9). We measured FeNO twice and averaged these as a continuous, log‐transformed outcome. We performed linear regression models, adjusted for child age, sex, height, and race/ethnicity, maternal education and smoking during pregnancy, household income and smoking, and neighbourhood characteristics. In secondary analysis, we additionally adjusted for asthma. More than 2 hours spent watching TV was associated with 10% lower FeNO (95% confidence interval [CI]: ?20, 0%). Higher body fat percentage was also associated with lower FeNO. After additional adjustment for asthma, teens who are underweight (BMI <5th %tile, 3%) had 22% lower FeNO (95%CI: ?40, 2%) and teens who are overweight (BMI ≥85th %ile, 28%) had 13% lower FeNO (95%CI: ?23, ?2%). Each of these associations of lifestyle and body weight with lower FeNO were greater in magnitude after adjusting for asthma. In summary, sedentary lifestyle, high and low BMI were all associated with lower FeNO in this adolescent cohort.     

Validity and reliability of measures of television viewing time and other non-occupational sedentary behaviour of adults: a review

Time spent in non-occupational sedentary behaviours (particularly television viewing time) is associated with excess adiposity and an increased risk of metabolic disorders among adults; however, there are no reviews of the validity and reliability of assessing these behaviours. This paper aims to document measures used to assess adults' time spent in leisure-time sedentary behaviours and to review the evidence on their reliability and validity. Medline, CINAHL and Psych INFO databases and reference lists from published papers were searched to identify studies in which leisure-time sedentary behaviours had been measured in adults. Sixty papers reporting measurement of at least one type of leisure-time sedentary behaviour were identified. Television viewing time was the most commonly measured sedentary behaviour. The main method of data collection was by questionnaire. Nine studies examined reliability and three examined validity for the questionnaire method of data collection. Test–retest reliabilities were predominantly moderate to high, but the validity studies reported large differences in correlations of self-completion questionnaire data with the various referent measures used. To strengthen future epidemiological and health behaviour studies, the development of reliable and valid self-report instruments that cover the full range of leisure-time sedentary behaviour is a priority.