Can anthropometry and physical fitness testing explain physical activity levels in children and adolescents with obesity?

ObjectivesAs time with patients and resources are increasingly limited, it is important to determine if clinical tests can provide further insight into real-world behaviors linked to clinical outcomes. The purpose of this study was to determine which aspects of anthropometry and physical fitness testing are associated with physical activity (PA) levels among youth with obesity.DesignCross-sectional study.MethodAnthropometry [height, waist circumference, bodyweight, fat percentage], physical fitness [muscular endurance (partial curl-ups), flexibility (sit-and-reach), lower-body power (long-jump), upper-body strength (grip), speed/agility (5 × 5-m shuttle), cardiorespiratory fitness (VO₂-max)], and PA [light (LPA), moderate (MPA), vigorous (VPA), MVPA] was assessed in 203 youth with obesity.ResultsThe sample was stratified by age <12 yrs (children); 12 yrs (adolescents) and sex. Stepwise regression evaluated associations between PA with anthropometry and physical fitness. Children (57% male) and adolescents (45% male) had a BMI Z-score of 3.5(SD:0.94) and 3.1(SD:0.76) respectively. Long-jump explained 19.5% [(Standardized) Beta = 0.44; p = 0.001] of variance in VPA for childhood girls and 12.6% (Beta = 0.35; p = 0.025) of variance in MPA for adolescent boys. 5 × 5-m shuttle explained 8.4% (Beta = −0.29; p = 0.042) of variance in MVPA for childhood girls. Body mass explained 6.3% (Beta = −0.25; p = 0.007) of variance in LPA in childhood boys. Fat percentage explained 9.8% (Beta = 0.31; p = 0.03) of variance in MPA in adolescent girls.ConclusionsIn conclusion, tests of lower body power, body mass and fat percentage provide limited information concerning PA levels in youth with obesity. Activity monitoring should be considered in addition to clinical assessments to more fully understand youth health.     

Age and gender differences in youth physical activity: does physical maturity matter?

PURPOSE: To investigate whether observed gender differences in objectively measured physical activity (PA) in children (8-13 yr) are confounded by physical maturity differences. METHODS: Four hundred and one children (194 boys and 207 girls) volunteered for this study. An Actigraph accelerometer was used to obtain seven consecutive days of minute-by-minute PA data for each participant. Minutes of moderate to vigorous PA per day (MVPA), continuous minutes of MVPA per day (CMVPA), and minutes of vigorous PA per day (VPA) were derived from the accelerometer data. Age at peak height velocity (APHV), an indicator of somatic maturity, was predicted in all individuals. Gender differences in the PA variables were analyzed using a two-way (gender x age) ANOVA. RESULTS: Levels of PA decreased with increasing chronological age in both genders (P < 0.05). When aligned on chronological age, boys had a higher MVPA at 10-13 yr, a higher CMVPA at 9-12 yr, and a higher VPA at 9-13 yr (P < 0.05). When aligned on biological age, PA declined with increasing maturity (P < 0.05); however, gender differences between biological age groups disappeared. CONCLUSION: The observed age-related decline in adolescent boys and girls PA is antithetical to public health goals; as such, it is an important area of research. To fully understand gender disparities in PA, consideration must be given to the confounding effects of physical maturity.     

Comparison of physical activity in male and female children: does maturation matter?

PURPOSE: To investigate whether observed differences in physical activity levels in boys and girls are confounded by biological age differences particularly during the circumpubertal years. METHODS: The physical activity questionnaire for children (PAQ-C) was administered biannually or triannually to 138 (70 boys; 68 girls) Canadian children for seven consecutive years from 1991 to 1997. Participants were 9-18 yr of age. Anthropometric measurements were taken biannually and age at peak height velocity (PHV) determined. Biological age was defined as years from PHV. The data were analyzed using t-tests and random effects models. RESULTS: Level of physical activity decreased with increasing chronological age in both sexes. When aligned on chronological age bands, boys had statistically significantly higher PAQ-C summary scores than girls from 10 through 16 yr of age (P < 0.05). However, when aligned on biological age, sex differences were not apparent, except at 3 yr before PHV. Random effects models of individual growth patterns confirmed these findings. CONCLUSION: Physical activity decreased with increasing chronological age in boys and girls. There were no sex differences in the longitudinal pattern of physical activity when the confounding effects of biological age were controlled except at 3 yr before PHV.     

Does physical activity reduce the risk of developing peptic ulcers?

BACKGROUND: Although Helicobacter pylori has been identified as a major cause of chronic gastritis, not all infected patients develop ulcers, suggesting that other factors such as lifestyle may be critical to the development of ulcer disease. AIM: To investigate the role physical activity may play in the incidence of peptic ulcer disease. METHODS: The subjects were men (8529) and women (2884) who attended the Cooper Clinic in Dallas between 1970 and 1990. The presence of gastric or duodenal ulcer disease diagnosed by a doctor was determined from a mail survey in 1990. Subjects were classified into three physical activity groups according to information provided at the baseline clinic visit (before 1990): active, those who walked or ran 10 miles or more a week; moderately active, those who walked or ran less than 10 miles a week or did another regular activity; the referent group consisting of those who reported no regular physical activity. RESULTS: With the use of gender specific proportional hazards regression models that could be adjusted for age, smoking, alcohol use, body mass index, and self reported tension, active men were found to have a significant reduction in risk for duodenal ulcers (relative hazard (95% confidence interval) for the active group was 0.38 (0.15 to 0.94) and 0.54 (0.30 to 0.96) for the moderately active group). No association was found between physical activity and gastric ulcers for men or for either type of ulcer for women. CONCLUSIONS: Physical activity may provide a non-pharmacological method of reducing the incidence of duodenal ulcers among men.     

How physical activity,diet, and sedentary behavior cluster according to age in adolescents?

Background

Clusters’ behaviors can change with age, moving from adolescence to adulthood.

Aims

This study examined physical activity (PA), diet, and sedentary behavior (SB) clusters according to age groups (11–12, 13–15, 16–17, and 18–19 years) and its association with sex and maternal education.

Methods

Brazilian National School-based Health Survey (PeNSE 2015) (n?=?16,522) data were analysed. Adolescents responded PA; consumption of fruits, vegetables; snacks, salt, and beverages (SSB); and SB. Two-step cluster analysis and Rao-Scott Chi square test were used.

Results

The Actives; the All-day sitters; the Inactive 1 (with moderate consumption of F&V); and the Inactive 2 (with small consumption of F&V and SSB) clusters were identified. The Actives and All-day sitters existed in all age groups. The Inactive 1 were the cluster more prevalent in 11–12 (33.9%), 13–15 (42.5%) and 16–17 (43.8%) age groups while, All-day sitters were most prevalent in 18–19 (43.7%) age group. Boys were more likely to be in the Actives; as against girls in All-day sitters, Inactive 1 and 2 clusters. The Actives had a higher proportion of adolescents with low maternal education.

Conclusions

SB increase in clusters over the increase of age group; else, adolescents in Actives groups decreased.

     

Effects of high altitude on substrate use and metabolic economy: cause and effect?

In a variety of experimental models, hypoxia causes a shift in substrate use to favor increased dependence on glucose. One explanation for this phenomenon is a selective advantage derived from the increased metabolic economy (more ATP derived per unit oxygen consumed) that results when glucose is oxidized rather than lipid. In support of this hypothesis, after acclimatization to hypoxia, lower oxygen consumption at a given submaximal workload has often been reported. However, evidence from several experimental models is inconsistent with the idea that the increase in glucose use is causally related to greater metabolic economy.     

Feasibility and effect of a physical activity counselling session with or without provision of an activity tracker on maintenance of physical activity in women with breast cancer — A randomised controlled trial

ObjectivesThe SAFE-Maintain study sought to evaluate the effect and acceptability of a physical activity counselling (PAC) session, versus a PAC session plus provision of a Fitbit (Charge HR®; PAC + F), on maintenance of physical activity levels 12 weeks following participation in a supervised exercise intervention.DesignFifty-two women with stage II + breast cancer who had recently (within the previous 7 days) completed a 12-week supervised exercise program were randomised to the PAC or PAC + F group.MethodsPhysical activity levels, including weekly minutes of total physical activity (min/week), daily step count (steps/day), and weekly minutes of moderate to vigorous physical activity (MVPA, min/week), were assessed using the Active Australia survey and Actigraph® GT3X+ accelerometers. Self-reported outcomes were assessed at baseline and 12-week follow-up, while objectively-measured outcomes were only available at 12-week follow-up.ResultsCompared with the PAC group, the PAC + F group had higher self-reported MVPA and self-reported total activity (between-group mean difference: 78.2 [95% CI = −8.3, 164.9] min/week, p < 0.01, and 171.9 [95% CI = 46.1, 297.8] min/week, p < 0.01, respectively) at 12-week follow-up. Higher objectively-assessed MVPA (p = 0.03) and steps/day (p = 0.07) at 12-week follow-up was also observed in the PAC + F group compared with the PAC group. Most (>80%) of the PAC + F group reported high levels of Fitbit use and considered the device to be beneficial for physical activity maintenance.ConclusionsFindings suggest that activity trackers show promise as an effective, feasible and acceptable approach to support physical activity maintenance following completion of a supervised exercise intervention.Trial registrationProspectively registered on the Australian and New Zealand Clinical Trials Registry (ANZCTR, Trial registration number: ACTRN12616000954426).     

Do logbooks influence recall of physical activity in validation studies?

PURPOSE: To examine whether physical activity logbooks influence estimates of validity of 7-d recall physical activity questionnaires. METHODS: A convenience sample of 551 adults aged 18-75 yr wore an MTI accelerometer for seven consecutive days and were then randomly administered two of four 7-d recall physical activity questionnaires that varied in length and format (Active Australia Survey (AAS), long and short International Physical Activity Questionnaires (IPAQ-L and IPAQ-S), and Behavioral Risk Factor Surveillance System (BRFSS)). A subsample of 75% concurrently completed a physical activity logbook. RESULTS: Correlations (rho) between self-reported and measured duration of moderate- and vigorous-intensity activity and total activity were similar among participants who received a logbook and those who did not for each of the four instruments. There was also no interaction between assessment method (survey, accelerometer) and the assignment of a logbook. For the IPAQ-L, however, variability in the difference between accelerometer data and responses to the vigorous items was smaller among those assigned a logbook (F = 4.128, df = 260, P = 0.043). Overall, there were no differences in percent agreement or kappa for participation in sufficient levels of physical activity according to receipt of a logbook for any of the surveys. CONCLUSION: The process of self-monitoring through completion of a logbook does not appear to influence estimates of validity for brief or long questionnaires with global questions. Whereas the magnitude of error in accuracy of recall of particular types of activity may be reduced by completion of a logbook that is similar in structure to the survey being validated, this does not appear to influence overall estimates of validity.     

Low physical activity and obesity: causes of chronic disease or simply predictors?

BACKGROUND AND PURPOSE: Many studies have shown associations between risk of morbidity and mortality with both obesity and low physical activity (PA), but association does not imply causality. Moreover, there is an inverse relationship between PA and obesity; therefore, controlling for one of these factors when investigating the risk associated with the other is essential. The purpose of this review is to determine whether low PA and obesity actually cause metabolic dysfunction and chronic disease, especially type 2 diabetes (T2D), rather than simply operating as predictors or markers. METHODS: The case for causality is strengthened if the following two conditions are satisfied: first, that significant associations between obesity or low PA and risk persist after controlling appropriately; and second, that the physiological mechanisms by which obesity or low PA may exert a causal effect are clearly established. The studies examined include those that have used cardiorespiratory (CR) fitness as a surrogate measure for PA, thus also providing evidence for low CR fitness as an independent risk factor in its own right. RESULTS AND CONCLUSIONS: Low PA and poor CR fitness are independent predictors of mortality related to type 2 diabetes and chronic disease in general. Together with well-demonstrated mechanisms, there is strong evidence that low PA and low CR fitness are direct, independent causes of metabolic dysfunction and type 2 diabetes. Despite some reports to the contrary, there is evidence that both general and visceral obesity are predictors of mortality and morbidity after controlling for PA. However, in the absence of established mechanisms, evidence is insufficient to conclude that either general or visceral obesity is a direct, independent cause of metabolic dysfunction or type 2 diabetes.     

Injury prevention and the promotion of physical activity: What is the nexus?

The promotion of physical activity is a public health priority for Australia. The new "National Physical Activity Guidelines for Australians" include a statement on additional health benefits of vigorous sporting and fitness activities. However, injury associated with sport and physical activity can lead to significant health care costs and consequent disabilities and reduced mobility may result in inactivity, this increasing the risk of cardiovascular disease and other health problems. Consideration of injury prevention principles when promoting physical activity is therefore crucial. There are several areas of research needed in this new field. These include the importance of good quality population monitoring and the use of other data sources to determine the population-wide consequences and health costs of injury sustained during sport and physical activity. The goal is to have evidence based, educational, regulatory and other preventive strategies that can be systematically evaluated by drawing on well organised, representative population-based injury data.     

Is sport enough? Contribution of sport to overall moderate- to vigorous-intensity physical activity among adolescents

ObjectivesThis study examined the contribution of sports participation to overall moderate-to-vigorous physical activity (MVPA) among adolescents, and explored potential moderators.DesignCross-sectional observational study using survey and accelerometry data drawn from the NEighbourhood Activity in Youth (NEArbY) study.MethodsAdolescents (n = 358) were recruited from secondary schools in Melbourne, Australia. Average min/day in MVPA was assessed using accelerometry. Participants self-reported sports participation (number of teams, type, frequency, and months of participation). Regression models determined the percent variance in MVPA explained by the sport variables, adjusted for wear time, age and sex, and accounting for clustering at the school level. Additional analyses tested if age, sex, body mass index (BMI), and socioeconomic status (SES) moderated relationships between sport variables and MVPA.ResultsParticipants (mean 15.3 years, 59% female) spent a mean (SD) of 68.6 (27.4) min/day in MVPA and 50% reported participating in any sport. Those who participated in sport did so 3.4 times/week on average and accumulated 7 min/day of MVPA more than those who did no sport. For each additional sport participated in, on average, there were approximately 5 additional min/day of MVPA. The number and frequency of sports participation explained 3.2% and 3.8% of the variance in MVPA respectively. Participation in field hockey and gymnastics explained 2.2% and 3.6% of the variance in MVPA, respectively. There were no moderating effects.ConclusionsSport appears to make a very small contribution to adolescents’ average daily physical activity. Effectiveness of approaches to increasing youth population levels of physical activity via sports participation needs to be tested.     

Does physical activity impact on presenteeism and other indicators of workplace well-being?

The term 'presenteeism' is a relatively new concept in workplace health, and has come to signify being at work despite poor health and performing below par. Presenteeism, which is potentially critical to employers, has been associated with a range of psychosocial outcome measures, such as poor mental health and employee well-being. Physical activity is a potential strategy for reducing presenteeism, and for improving the mental health of employees. This article reviews evidence on the relationships between physical activity and employee well-being and presenteeism in the workplace, and identifies directions for research in an emerging field. Electronic and manual literature searches were used to identify 20 articles that met the inclusion criteria. These included 13 intervention trials (8 randomized controlled trials, 5 comparison trials) and 7 observational studies (3 cohort, 4 cross-sectional). Outcome measures were grouped into 'workplace well-being', 'psychosocial well-being' and 'physical well-being'. Studies measured a wide variety of outcomes, with absenteeism being the most commonly assessed. Evidence indicated a positive association between physical activity and psychosocial health in employees, particularly for quality of life and emotional well-being. However, findings were inconclusive as to the role of physical activity in promoting workplace well-being. Only one study reported on presenteeism, with mixed evidence for outcomes. This article indicates that physical activity and employee psychosocial health are positively related, but there is limited evidence of a relationship between physical activity and presenteeism. A standardized definition of presenteeism and an appropriate evaluation tool are key research priorities if the complex relationships between physical activity and workplace well-being are to be better understood.     

Carcinogenicity of radon/radon decay product inhalation in rats – effect of dose,dose rate and unattached fraction

Purpose: The effects of inhalation of radon/radon decay products at different total doses, dose rates and ‘unattached’ fractions were investigated in a life span study in rats.

Materials and methods: 1574 rats inhaled radon/radon decay products in a purpose-built recirculating exposure system that provided stable/reproducible exposure conditions. 501 were maintained as controls.

Results: Lung tumour incidences were significantly elevated in most exposed groups. The study power was insufficient to resolve the shape of the dose and dose rate response curves, but combination of this data with that from other studies demonstrated that for high cumulative exposures, the lifetime excess absolute risk increases with increasing exposure durations and for low cumulative exposures the opposite trend occurs. Exposure did not increase leukaemia incidences. A small number of non-lung tumour types including mammary fibroadenoma showed elevated incidences in some exposed groups, however not consistently across all exposure groups and showed no dose or dose rate relationship.

Conclusions: Radon/radon decay product exposure caused excess lung tumours in rats along with limited non-lung effects. The results are consistent with the findings that at low cumulative exposures decreasing exposure concentrations or protracting the time over which the dose is delivered, reduces lung tumour risk. At higher levels, decreasing exposure concentrations or protracting exposure time increases lung tumour risk.