Association of daily sitting time and leisure-time physical activity with body fat among U.S.adults

Background:Prolonged sitting and reduced physical activity lead to low energy expenditures.However,little is known about the joint impact of daily sitting time and physical activity on body fat distribution.We investigated the independent and joint associations of daily sitting time and physical activity with body fat among adults.Methods:This was a cross-sectional analysis of U.S.nationally representative data from the National Health and Nutrition Examination Survey2011-2018 among adults aged 20 years or older.Daily sitting time and leisure-time physical activity(LTPA)were self-reported using the Global Physical Activity Questionnaire.Body fat(total and trunk fat percentage)was determined via dual X-ray absorptiometry.Results:Among 10,808 adults,about 54.6%spent 6 h/day or more sitting;more than one-half reported no LTPA(inactive)or less than 150 min/week LTPA(insufficiently active)with only 43.3%reported 150 min/week or more LTPA(active)in the past week.After fully adjusting for sociodemographic data,lifestyle behaviors,and chronic conditions,prolonged sitting time and low levels of LTPA were associated with higher total and trunk fat percentages in both sexes.When stratifying by LTPA,the association between daily sitting time and body fat appeared to be stronger in those who were inactive/insuufficiently active.In the joint analyses,inactive/insuufficiently active adults who reported sitting more than 8 h/day had the highest total(female:3.99%(95%confidence interval(95%CI):3.09%-4.88%);male:3.79%(95%CI:2.75%-4.82%))and trunk body fat percentages(female:4.21%(95%CI:3.09%-5.32%);male:4.07%(95%CI:2.95%-5.19%))when compared with those who were active and sitting less than 4 h/day.Conclusion:Prolonged daily sitting time was associated with increased body fat among U.S.adults.The higher body fat associated with 6 h/day sitting may not be offset by achieving recommended levels of physical activity.

Validity of long-term and short-term recall of occupational sitting time in Finnish and Chinese office workers

Background:As sedentary behavior is a global health issue,there is a need for methods of self-reported sitting assessment.The accuracy and reliability of these methods should also be tested in various populations and different cultural contexts.This study examined the validity of longterm and short-term recall of occupational sitting time in Finnish and Chinese subgroups.Methods:Two cohort groups of office-based workers(58.6%female,age range 22
67 years)participated:a Finnish group(FIN,n=34)and a Chinese group(CHI,n=36).Long-term(past 3-month sitting)and short-term(daily sitting assessed on 5 consecutive days)single-item measures were used to assess self-reported occupational sitting time.Values from each participant were compared to objectively measured occupational sitting time assessed via thigh-mounted accelerometers,with Spearman’s rho(r)used to assess validity and the Bland-Altman method used to evaluate agreement.Coefficients of variation depicted day-to-day variability of time spent on sitting at work.Results:In the total study sample,the results showed that both long-term and short-term recall correlated with accelerometer-derived sitting time(r=0.532,95%confidence intervals(CI):0.336
0.684,p<0.001;r=0.533,95%CI:0.449
0.607,p<0.001,respectively).Compared to objectively measured sitting time,self-reported occupational sitting time was 2.4%(95%CI:
0.5%to 5.3%,p=0.091)and 2.2%(95%CI:0.7%
3.6%,p=0.005)greater for long-term and short-term recall,respectively.The agreement level was within the range
21.2%to 25.9%for long-term recall,and
24.2%to 28.5%for short-term recall.During a 5-day work week,day-to-day variation of sitting time was 9.4%§11.4%according to short-term recall and 10.4%§8.4%according to accelerometry-derived occupational sitting time.Conclusion:Overall,both long-term and short-term self-reported instruments provide acceptable measures of occupational sitting time in an office-based workplace,but their utility at the individual level is limited due to large variability.

Does light-intensity physical activity moderate the relationship between sitting time and adiposity markers in adolescents?

Background:While the relationship between sedentary time and adiposity markers may be independent of moderate-to-vigorous intensity physical activity(MVPA) among adolescents,little is known about the role of light-intensity physical activity(LIPA) in this relationship.The aim of this cross-sectional study was to examine whether device-measured LIPA and MVPA moderate the associations between objectively measured sitting time and adiposity markers(body mass index(BMI)) and waist circumference(WC)) among adolescents.Methods:This study included accelerometer and inclinometer data obtained from 219 adolescents(age=14.9±1.6 years,mean± SD),collected during 2014 and 2015 in Melbourne,Australia.ActiGraph GT3 X accelerometers were used to determine time spent in total-LIPA(101 counts/min to 3.99 metabolic equivalents(METs)) was dichotomized into low-LIPA(101-799 counts/min) and high LIPA(800 counts/min to 3.99 METs),and MVPA(> 4 METs).The average time spent sitting was obtained from activPAL inclinometers.Anthropometric measures were assessed by trained staff.Interactions between sitting and total-LIPA,low-LIPA,high-LIPA,and MVPA on BMI z-score(zBMI) and WC z-score(zWC),respectively,were examined using linear regression,adjusting for age and sex;and moderation by total-LIPA,low-LIPA,high-LIPA,and MVPA were examined by adding interaction terms.Significant interaction effects were probed by comparing associations at the mean and at 1 SD below and above the mean.Results:Total-LIPA significantly moderated the association between sitting time and zBMI,and low-LIPA significantly moderated the association between sitting time and zBMI and zWC.No other associations were found for total-LIPA,high-LIPA,or MVPA.Specifically,at high levels of total-LIPA(+1 SD),there is a negative association between sitting time and zBMI.In addition,at high levels of low-LIPA(+1 SD),there is a negative association between sitting time and zBMI and zWC.Conclusion:Associations between sitting and adiposity depended on time spent in total-LIPA and low-LIPA,but not high-LIPA or MVPA.Results suggest that increasing time spent in LIP A may provide protection from the deleterious effects of sitting on adiposity markers among adolescents.Experimental evidence is needed to support these conclusions.

Factors Relevant to Knee Pain among Independent Community-Dwelling Older Adults: A Complete Cross-Sectional Study

Objective: Knee pain is commonly observed among older adults. Therefore, the prevention of knee pain in older adults is a major public health issue. This study aimed to clarify factors relevant to knee pain among older adults. Methods: This study targeted all independent older adults (N = 6661) living in a local municipality in Japan. Participants’ health status and lifestyle habits were surveyed using a questionnaire. The survey was conducted from 15 January to 14 February 2016. Relationships between knee pain and physical activity, sitting time, nutrition, drinking, smoking, or body mass index (BMI) were examined using logistic regression analysis. Odds ratios (OR) and 95% confidence intervals (CI) adjusted for several confounding factors were calculated. Results: Older adults of 5311 responded to the questionnaire and 1843 reported knee pain. The prevalence of knee pain was 34.8%. Knee pain was significantly associated with BMI (OR: 0.60, 95% CI: 0.51 - 0.69, P < 0.001 in the group of normal range, OR: 0.38, 95% CI: 0.29 - 0.51, P < 0.001 in the group of <18.0), nutrition status (OR: 0.63, 95% CI: 0.54 - 0.75, P < 0.001), and physical activity (OR: 0.81, 95% CI: 0.71 - 0.92, P = 0.001). Conclusions: This study suggests that one in three independently-living older adults experiences chronic knee pain and that physical activity, BMI, and nutritional status are associated with knee pain.

Associations between sociodemographic factors and physical activity and sedentary behaviors in adults with chronic diseases during COVID-19 pandemic

The pandemic of the new coronavirus(COVID-19)may be affecting the physical activity(PA)level in much of the population.This study aimed to investigate the prevalence of physical inactivity and sedentary behavior(SB)among adults with chronic diseases and their associations with sociodemographic factors during the COVID-19 pandemic.This cross-sectional study included 249 participants(age:18-91 years;61.4%female)with chronic conditions and attended the Family Health Strategy program in a small town in Brazil.Data were collected between 2020-07-13 and 2020-07-24 by face-to-face interviews.Self-reported PA,sitting time,chronic diseases,medication use,sociodemographic data,and self-isolation adherence were obtained by questionnaire.During this specific time point of the COVID-19 pandemic,71.5%of participants did not meet the PA recommendations(≥500 METs-min/week),and the prevalence of SB risk(≥4 h sitting)was 62.7%.Adjusted logistic regression indicated that male participants(odds ratio[OR]:1.89[95%CI 1.02-3.53]),living alone(OR:2.92[95%CI 1.03-8.30])or in a two-person household(OR:2.32[95%CI 1.16-4.63]),and those who reported sometimes performing self-isolation(OR:3.07[95%CI 1.47-6.40])were more likely to meet the minimum PA recommendations.Current smokers had a lower odds(OR:0.36[95%CI 0.14-0.95])of meeting the PA recommendations.Older participants(OR:2.18[95%CI 1.06-4.50])and those who had multimorbidity(OR:1.92[95%CI 1.07-3.44])were more likely to have a higher degree of SB.There is an urgent need to mitigate physical inactivity and SB,and public health interventions must take into account sociodemographic status.