Sitting time and physical function in Australian retirees: An analysis of bidirectional relationships

Please download to get full document.

View again

of 7
All materials on our website are shared by users. If you have any questions about copyright issues, please report us to resolve them. We are always happy to assist you.
Similar Documents
Information Report
Category:

Real Estate

Published:

Views: 0 | Pages: 7

Extension: PDF | Download: 0

Share
Description
Background: There is limited evidence on the directionality of the associations of sitting time with physical function. This study examined the longitudinal associations of sitting time with changes in physical function, and physical function with
Tags
Transcript
  © The Author(s) 2018. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com. 1 Journals of Gerontology: Medical Sciences  cite as: J Gerontol A Biol Sci Med Sci  ,   2018, Vol. 00, No. 00, 1–7doi:10.1093/gerona/gly008Advance Access publication February 2, 2018 Research Article Sitting Time and Physical Function in Australian Retirees: An Analysis of Bidirectional Relationships Paul A. Gardiner, PhD, 1,2  Natasha Reid, BSc, 3  Klaus Gebel, PhD, 4,5,6  and Ding Ding, PhD 5,6 1 Centre for Health Services Research, The University of Queensland, Woolloongabba, Australia. 2 Mater Research Institute, The University of Queensland, South Brisbane, Australia. 3 School of Public Health, The University of Queensland, Herston, Australia. 4 School of Allied Health, Australian Catholic University, North Sydney, New South Wales, Australia. 5 Prevention Research Collaboration, Charles Perkins Centre, Sydney School of Public Health, The University of Sydney, Camperdown, New South Wales, Australia. 6 Centre for Chronic Disease Prevention, College of Public Health, Medical and Veterinary Sciences, James Cook University, Smithfield, Queensland, Australia. Address correspondence to: Paul A. Gardiner, PhD, Centre for Health Services Research, The University of Queensland, Level 2, Building 33, Princess Alexandra Hospital, Woolloongabba, QLD 4102, Australia. E-mail: p.gardiner@uq.edu.auReceived: May 3, 2017; Editorial Decision Date: January 2, 2018 Decision Editor:  Anne Newman, MD, MPH Abstract Background: There is limited evidence on the directionality of the associations of sitting time with physical function. This study examined the longitudinal associations of sitting time with changes in physical function, and physical function with changes in sitting time. Methos: Data from 10,027 retirees in the Social, Economic, and Environmental Factor (SEEF) population-based cohort were collected in 2006–20008 and in 2010–2011. Daily sitting time was assessed by a single-item question. Physical function was measured with the Medical Outcomes Study Physical Functioning Scale (range 0–100) with participants categorized as: no; minor; moderate; or severe limitation. General linear regression models, adjusted for covariates, were used to assess associations of sitting time with physical function for all participants and in subgroups according to sex, and categories of body mass index, physical activity, and physical function limitations. Results: Each hour of baseline sitting was associated with declines in physical function for women (0.20 units [95% confidence interval {CI} 0.04–0.37]) and those with severe functional limitations (0.65 units [95% CI 0.20–1.12]). Each unit of baseline physical function was associated with declines in sitting time for all participants (0.009 hours/day [95% CI 0.005–0.013]) and for all subgroups. Conclusions: There was limited evidence of a bidirectional association of sitting time with physical function except in women and people with severe functional limitations. Health promotion efforts are needed to address the impact of poor physical function on increases in sitting time which result in further functional declines for these subgroups of the population. Keywords:  Sedentary behavior, Sitting time, Physical function, Population-based cohort, Longitudinal studies Globally, older adults are the fastest growing age group worldwide with the proportion of adults aged 65 years or more expected to increase to 22%, or 2 billion people, by 2050 (1). In Australia alone, population projections indicate that there will be over 11 million older adults by 2061, which represents one-fifth of the total pro-jected population (2). Unfortunately, little evidence is available to indicate that greater longevity is associated with maintained health during the later years of life (1). The maintenance of physical func-tion is an important aspect of health (3). Deteriorating physical function is pervasive in the aging process (4), and is associated with numerous detrimental health outcomes (1) and increased health-care burden (5).While moderate- to vigorous-intensity physical activity (MVPA) is an established means of maintaining function (6), emerging research indicates a relationship between sedentary time and func-tion in adults. Sedentary time refers to any waking activities in a seated or reclined posture with low energy expenditure (7) and is commonly referred to as sitting time. Two recent systematic reviews Downloaded from https://academic.oup.com/biomedgerontology/advance-article-abstract/doi/10.1093/gerona/gly008/4834950by Australian Catholic University useron 26 February 2018  report that older adults sit for approximately 9 hours per day (8,9) which represents 65%–80% of their waking hours (9) and makes them the population group with the highest levels of sitting time (8). Therefore, evaluating if and how sitting and function are associ-ated is particularly important in this population especially given the postulated role that reducing sitting time may have in getting older adults more active (10).A number of cross-sectional studies have reported that higher levels of sitting are associated with poorer physical function (11–16). This finding is consistent across measurement tools of seden-tary behavior (ie, self-reported (12) vs device measured (11)) and physical function (self-reported (15) vs performance based (11)), across multiple domains of functioning (ie, upper (12) and lower body function (16)). Some studies also suggest that this association is independent of levels of MVPA (11,14). One notable analysis including more than 60,000 participants from the Women’s Health Initiative Observational Study found that those in the lowest quartile of self-reported sedentary time reported better physical function (SF-36 physical function subscale) compared to participants in all higher quartiles of sedentary time (13). While these studies indicate an in-verse association between sedentary behavior and physical function, others have observed no (17–20) and one study even opposite (21) findings. These inconsistencies within the literature require further investigation.A major limitation of the current evidence base is the lack of longitudinal data. To the best of our knowledge, there have been only five longitudinal studies examining sedentary behavior and physical function (13–15,22,23). These studies found that higher levels of sedentary time are associated with both poorer self-reported (13,15,22) and performance based function (gait speed and five times sit to stand test (14), and knee extension strength (23).) However, no studies have examined the concurrent bidirectional associations between sedentary behavior and physical function (ie, does seden-tary behavior predict physical function and/or  vice versa?). This is important to investigate as evidence suggesting a bidirectional as-sociation may influence future intervention strategies. People with lower physical function have reduced capacity to move around and this may result in more time spent sitting. Given that we know that sedentary behavior is predictive of poorer health outcomes in older adults, if poor function results in more sitting time this increases the likelihood of further deteriorations in health. In addition, given the differences in sedentary behavior by sex (9,24), BMI categories (24), and levels of physical activity (25), subgroup analyses, investigating these moderating factors is imperative.To address these evidence gaps, the primary aim of this study was to investigate the longitudinal bidirectional associations of sed-entary behavior with physical function in older adults. Given that employment status is associated with sedentary time in older adults (24) and that retirement is associated with changes in sedentary time (26–28), we conducted the study in retirees. A further aim of this study was to investigate whether these associations differed by per-sonal characteristics (eg, sex, body mass index [BMI] category, age group) and health-related factors (physical activity category and functional limitations). Methods Sampling and Procedures Participants were drawn from the Social, Economic, and Environmental Factor study (SEEF) ( n  = 60,404), a follow-up of a subsample of the Sax Institute’s 45 and Up Study, which comprised 267,153 adults aged ≥45 years from the state of New South Wales, Australia. Baseline participants for the 45 and Up Study were surveyed between February 2006 and December 2009 (participation rate = 18%) (29). In 2010, the first 100,000 respond-ents were invited to participate in the SEEF study (response rate, 60.4%; 3.4 ± 0.95 years follow-up time). All participants completed consent forms for both surveys. The 45 and Up and SEEF stud-ies were approved by the University of New South Wales Human Research Ethics Committee (reference, HREC 05035) and the University of Sydney Human Research Ethics Committee (reference, 10–2009/12187).Our analyses were restricted to those who were retired at both baseline and follow-up, so that the change in sitting time refers to non-occupational settings only, and is not influenced by change in working situation. To minimize residual confounding from major chronic diseases and disability, and as a common practice by pre-vious studies on sedentary behavior (30,31), we further eliminated those with prior diagnosis of cardiovascular disease or cancer (ex-cept for nonmelanoma skin cancer), and those who reported need-ing help on daily tasks due to disability or long-term illness. The final sample size included 10,027 participants with complete data (Figure 1). Measures Participants completed a self-administered questionnaire at both baseline and follow-up (https://www.saxinstitute.org.au/ our-work/45-up-study/questionnaires/ ). Total daily sitting time was assessed using a single question “About how many hours in n=17,244n=23,729Total baseline samplen=60,412n=13,826n=13,388n=12,741n=11,255n=10,037n=10,027 Not retired at baselinen=36,683Had cardiovascular diseasen=6,485 Neededhelp for daily tasks dueto disability / long-term illnessn=438 No data on disability / long-term illnessn=647 Nositting data at both surveysn=1,486 Nophysical function dataat both surveysn=1,218Missing covariatesn=10Had previous cancer diagnosisn=3,418 Figure 1. Participant flow diagram: Selecting the analytical sample, Social, Economic, and Environmental Factor study (SEEF), New South Wales, Australia, 2006–2011. 2   Journals of Gerontology: MEDICAL SCIENCES  , 2018, Vol. 00, No. 00 Downloaded from https://academic.oup.com/biomedgerontology/advance-article-abstract/doi/10.1093/gerona/gly008/4834950by Australian Catholic University useron 26 February 2018  each 24-hour day do you usually spend sitting?” and expressed as hours/day. This is similar to the validated sitting question from the International Physical Activity Questionnaire (32). Physical function was measured with the 10-item Medical Outcomes Study Physical Functioning Scale (MOS-PF), which assesses functional capacity for daily activities. The MOS-PF uses a scale from 0 to 100 (lower values represent lower physical function) and has good reliability and validity (33–35). Following previous established cut-off points from the 45 and Up study, we categorized the MOS-PF score as follows: no physical limitation (100); minor limitation (90–99); moderate limitation (60–89); and severe limitation (0–59) (36). Change in sitting time or physical function was calculated as follow-up amount (sitting time) or score (MOS-PF)—baseline amount or score.Covariates included age, sex, marital status (partnered; single), educational attainment (school certificate or lower; high school/ trade/diploma; university or higher), location of residence (major cities; regional/remote), living situation (community dwelling; se-nior housing; other), and current smoking status (yes; no). MVPA was measured using the Active Australia Survey which has accept-able reliability and validity (37,38). BMI categories, derived from self-reported height and weight, include underweight (<18.5 kg/m 2 ), normal weight (≥18.5 kg/m 2  to <25 kg/m 2 ), overweight (≥25 kg/ m 2  to <30 kg/m 2 ), and obese (≥30 kg/m 2 ). A previous study found high agreement between measured and self-reported BMI categories among the 45 and Up participants (39). Statistical Analysis To assess potential bidirectional associations between sitting time and physical function, we conducted two analyses in STATA 13.0 (College Station, TX). In Analysis 1 , we examined whether sitting time at base-line is associated with functional decline during the follow-up by regressing baseline sitting time (hours/day) on change in the MOS-PF score (as a continuous variable). In Analysis 2 , we examined whether functional limitations at baseline are associated with change in sitting time during the follow-up by regressing baseline physical function categories on change in sitting time (hours/day).Both analyses used general linear regression with covariates entered to the models sequentially: Model 1 adjusted for the baseline value of the outcome and follow-up time, Model 2 add-itionally adjusted for age, sex, marital status, educational attain-ment, location of residence, living situation, and smoking, Model 3 further included BMI categories, and Model 4 added MVPA categories as an additional covariate. Unstandardized regression coefficients were reported for the overall sample, and by sex, age categories, BMI categories, levels of MVPA, and physical function at baseline (for Analysis 1 only). Table 1.  Baseline (2006–2008) Characteristics of Participants, N   = 10,027, New South Wales, Australia Men ( N   = 4,626)Women ( N   = 5,401)Overall Sample ( N   = 10,027)Age in years, mean ( SD )70.1 (7.9)67.8 (7.8)68.9 (7.9)Age category 45–59 y367 (7.9)793 (14.7)1,160 (11.6) 60–74 y2,999 (72.8)3,593 (66.5)6,592 (65.7) 75+ y1,260 (27.2)1,015 (18.8)2,275 (22.7)Marital status Single/divorced/widowed/separated756 (16.3)1,600 (29.6)2,356 (23.5) Married/de-facto3,870 (83.7)3,801 (70.1)7,671 (76.5)Educational attainment School certificate or lower1,190 (25.7)2,491 (46.1)3,681 (36.7) High school/trade/diploma2,318 (50.1)1,987 (36.8)4,305 (42.9) University or higher1,118 (24.2)923 (17.1)2,041 (20.4)Location of residence Major cities2,601 (56.2)3,291 (60.9)4,135 (41.2) Regional/remote2,025 (43.8)2,110 (39.1)5,892 (58.8)Living situation Community dwelling4,387 (94.8)5,067 (93.8)9,454 (94.3) Senior housing (hostel for the aged, nursing home, retirement village)230 (5.0)316 (5.9)546 (5.5) Other9 (0.2)18 (0.3)27 (0.3)Current smoker Yes177 (3.8)206 (3.8)383 (3.8) No4,449 (96.2)5,195 (96.2)9,644 (96.2)Body mass index a  Underweight37 (0.8)82 (1.5)119 (1.2) Normal1,645 (35.6)2,292 (42.4)3,937 (39.3) Overweight2,161 (46.7)1,952 (36.1)4,113 (41.0) Obese783 (16.9)1,075 (19.9)1,858 (18.5)Baseline sitting time in hours/day, mean ( SD )5.2 (2.6)4.9 (2.5)5.1 (2.6)Change in sitting time in hours/day, mean ( SD )−0.40 (3.00)−0.34 (2.65)−0.37 (2.81)Baseline physical function score, mean ( SD ) b 85.9 (17.9)83.2 (19.7)84.5 (18.9)Change in physical function score, mean ( SD )−3.98 (16.6)−4.52 (16.1)−4.30 (16.3) Note : Data are n  (%) except where indicated; SD = Standard deviation. a Body mass index (BMI) was calculated from self-reported height and weight and categorized as: underweight (<18.5 kg/m 2 ), normal weight (≥18.5 kg/m 2  to <25 kg/m 2 ), overweight (≥25 kg/m 2  to <30 kg/m 2 ), and obese (≥30 kg/m 2 ). b Physical function was measured using the 10-item Medical Outcomes Study Physical Functioning Scale (MOS-PF) (35), a scale from 0 to 100 (with higher values representing better function). Journals of Gerontology: MEDICAL SCIENCES,  2018, Vol. 00, No. 00 3 Downloaded from https://academic.oup.com/biomedgerontology/advance-article-abstract/doi/10.1093/gerona/gly008/4834950by Australian Catholic University useron 26 February 2018  Results Descriptive statistics of participants are presented in Table 1. On average, the participants were almost 70 years old, 54% were fe-male, and 20% had a university degree. The mean daily sitting time at baseline was 5.1 hours and the average physical function score was 84.5. The proportions of people in each category of functional limitation and the means ( SD ) of daily sitting time were: no limita-tion, 27.1% (4.6 hours/day, SD  = 2.5); minor limitations, 32.2% (5.0 hours/day, SD  = 2.5), moderate limitations, 29.4% (5.1 hours/ day, SD  = 2.6); and severe 11.3% (5.6 hours/day, SD  = 3.1). During the follow-up, participants reduced their sitting time by an average of 0.37 hours/day ( SD  2.8) and their physical function declined by 4.3 points ( SD  = 16.3). Association Between Baseline Sitting Time and Change in Physical Function In the overall model for all participants, the effect size for changes in physical function by baseline sitting time became incrementally smaller as more covariates were added to the models, that is, from Model 1 to Model 4 and were nonsignificant for Models 3 and 4. The patterns of association were similar for most subgroups, ex-cept for sex and physical function. The effect size was much larger for women and there was almost no effect among men (  p  for inter-action = .049). In addition, there was significant effect modification by baseline physical function. Those with the most severe limita-tions had the largest effect sizes, while there was almost no effect for those with minor or moderate limitations at baseline. The effects were larger among those that were not sufficiently physically active at baseline, but the  p  for interaction by activity categories was non-significant. Adjusting for physical activity category attenuated the effect size in women and those with severe functional limitations, but the association remained statistically significant in the fully adjusted models. For each additional hour of sitting at baseline, there was a 0.20 (95% CI 0.04–0.37) and 0.65 (95% CI 0.20–1.12) unit de-crease in physical function for women and people with severe limita-tions at baseline, respectively (Table 2). Association Between Baseline Physical Function and Change in Daily Sitting Time There were significant and consistent associations between baseline functional limitations and change in sitting over time. In the entire sample, for each additional unit in baseline physical function, sit-ting time decreased by 0.009 (95% CI 0.007–0.011) hours/day. The largest effect was seen in underweight people, where each additional Table 2.  Association of Baseline Daily Sitting Time With Change in Physical Function From Baseline (2006–2008) to Follow-up (2010–2011), N   = 10,027, New South Wales, Australia Model 1 a B (95% CI)Model 2 b B (95% CI)Model 3 c B (95% CI)Model 4 d B (95% CI)All participants−0.15 (−0.27, −0.03)*−0.14 (−0.26, −0.02)*−0.11 (−0.22, 0.01)−0.09 (−0.21, 0.03) Subgroup analyses Sex Men−0.04 (−0.22, 0.14)−0.01 (−0.20, 0.20)0.00 (−0.17, 0.17)−0.01 (−0.16, 0.18) Women−0.29 (−0.46, −0.12)**−0.26 (−0.43, −0.10)**−0.21 (−0.28, −0.05)*−0.20 (−0.37, −0.04)*Age category 45–59 y−0.15 (−0.46, 0.16)−0.12 (−0.43, 0.19)−0.08 (−0.39, 0.23)−0.08 (−0.39, 0.23) 60–74 y−0.07 (−0.21, 0.07)−0.11 (−0.25, 0.04)−0.08 (−0.22, 0.06)−0.08 (−0.22, 0.06) 75+ y−0.24 (−0.53, 0.06)−0.26 (−0.56, 0.04)−0.24 (−0.54, 0.06)−0.21(−0.50, 0.09)BMI category e  Underweight0.01 (−1.16, 1.18)0.03 (−1.09, 1.15)-- h 0.11 (−1.03, 1.25) Normal weight−0.09 (−0.27, 0.09)−0.04 (−0.22, 0.14)-- h −0.03 (−0.21, 0.15) Overweight−0.15 (−0.35, 0.04)−0.14 (−0.33, 0.05)-- h −0.13 (−0.32, 0.06) Obese−0.18 (−0.48, 0.12)−0.14 (−0.44, 0.16)-- h −0.11 (−0.41, 0.19)MVPA category f   <150 min/week−0.38 (−0.72, −0.05)*−0.33 (−0.66, −0.01)*−0.30 (−0.62, 0.03)-- i  150–299 min/week0.14 (−0.20, 0.47)0.10 (−0.23, 0.43)0.13 (−0.20, 0.46)-- i  >300 min/week−0.09 (−0.23, 0.05)−0.08 (−0.22, 0.05)−0.06 (−0.20, 0.08)-- i Physical function at baseline g  No limitation−0.17 (−0.35, 0.14)−0.17 (−0.35, 0.14)−0.15 (−0.33, 0.03)−0.15 (−0.33, 0.03) Minor limitation0.02 (−0.15, 0.20)0.02 (−0.16, 0.19)0.04 (−0.14, 0.21)0.05 (−0.13, 0.23) Moderate limitation−0.01 (−0.26, 0.25)0.01 (−0.25, 0.25)0.04 (−0.21, 0.29)0.05 (−0.20, 0.30) Severe limitation−0.85 (−1.33, −0.38)***−0.78 (−1.23, −0.32)***−0.74 (−1.20, −0.28)**−0.65 (−1.12, −0.20)** Note : BMI = Body mass index; MVPA = Moderate- to vigorous-intensity physical activity. a Model 1: Adjusted for baseline MOS-PF score and follow-up time only. b Model 2: Adjusted for variables in Model 1+ age, sex, marital status, educational attainment, location of residence, living situation, and smoking. c Model 3: Adjusted for variables in Model 2 + body mass index (BMI) category. d Model 4: Adjusted for variables in Model 3 + moderate-to-vigorous physical activity category. e BMI was calculated from self-reported height and weight and categorized as: under-weight (<18.5 kg/m 2 ), normal weight (≥18.5 kg/m 2  to <25 kg/m 2 ), overweight (≥25 kg/m 2  to <30 kg/m 2 ), and obese (≥30 kg/m 2 ). f  Moderate-to-vigorous physical activity (MVPA) was measured using the Active Australia questionnaire (37). g Physical function was measured using the 10-item Medical Outcomes Study Physical Functioning Scale (MOS-PF) (35), a scale from 0 to 100 (with higher values representing better function). When scores were categorized, the following cut-off points were used: no limitation (100); minor limitation (90–99), moderate limitation (60–89), severe limitation (0–59) (36). h The variable of BMI category was omitted from the model and therefore Model 3 was identical to Model 2. i The variable of MVPA category was omitted from the model and therefore Model 4 was identical to Model 3.*  p  < .05; **  p  < .01; ***  p  < .001; Effect modification by the following variables have reached statistical significance at  p  < .05: sex, baseline physical function. 4   Journals of Gerontology: MEDICAL SCIENCES  , 2018, Vol. 00, No. 00 Downloaded from https://academic.oup.com/biomedgerontology/advance-article-abstract/doi/10.1093/gerona/gly008/4834950by Australian Catholic University useron 26 February 2018  unit in physical function at baseline was associated with a decrease of 0.032 (95% CI 0.012–0.051) hours/day in sitting time, or for every 10 additional units, there was a 2.24 hours/week reduction in sitting time (Table 3). Similar to the associations of baseline sitting time with physical function at follow-up, effect sizes became smaller as models were adjusted for additional covariates of BMI and phys-ical activity categories (Models 3 and 4). In contrast, the associa-tions of baseline physical function with follow-up sitting time were not attenuated to the null and they remained statistically significant (Table 3). This pattern was consistent among all subgroups (  p  for interaction was nonsignificant for all comparisons). Discussion This is the first study to assess bidirectional relationships of sitting time with physical function. Sitting time predicted declines in phys-ical function in women, but not in men and only in those with severe functional limitations at baseline and not in those with no, minor, or moderate limitations. There was no effect across categories of age, BMI, or MVPA. In contrast, baseline physical function predicted change in sitting time over the follow-up period in all participants and across all subgroups.Our finding that the association between baseline sedentary time and decline in physical function at follow-up only applied to women and those with the most severe functional limitations at baseline is in contrast to previous studies that have examined this relationship (13–15,22,23). All of these studies showed that high levels of seden- tary time predicted poorer physical function in at least one measure of function at follow-up (13–15,22,23). Our average follow-up time of 3.4 years is less than some previous studies which had a follow-up time of 6 (15,22), 9 (30), or 12 years (13,23). As we excluded people who needed assistance in daily tasks, it is possible that our follow-up period was not long enough to observe an impact of sitting on phys-ical function in more subgroups of our relatively healthy population. It is also plausible that objective performance tests are more sensitive to smaller functional declines than self-reported variables as the lat-ter require the participant to have noticed and acknowledged a limi-tation. In one study with a shorter follow-up period of 2 years (14), the participants all had knee osteoarthritis or risk factors for that condition. It is possible that these participants had physical function limitations. Similarly, in our study, we observed that sitting time was associated with declines in function at follow-up in people with se-vere limitations in function at baseline.To our knowledge, this is the first study to examine the impact of physical function on sitting time at follow-up. The finding that middle-aged and older people with poorer physical function increase their sitting over time is not surprising. Coupled with the finding that sitting time is associated with physical function declines in people with severe limitations indicates a vicious circle where poorer phys-ical function leads to increased sitting time, which leads to further functional declines. Given that high levels of sitting time are pre-dictive of premature mortality (40,41), and in older adults associated with cardiometabolic disease, for example, the metabolic syndrome (42), measures should be taken to address factors such as poor phys-ical function that increase sitting time. Intervention trials should test whether improving physical function has any impact on sitting time. Table 3.  Association of Baseline Physical Function a  With Change in Daily Sitting Time From Baseline (2006–2008) to Follow-up (2010–2011), N   = 10,027, New South Wales, Australia Model 1 d B (95% CI)Model 2 e B (95% CI)Model 3 f  B (95% CI)Model 4 g B (95% CI)All participants−0.011 (−0.013, −0.009)***−0.010 (−0.013, −0.009)***−0.010 (−0.012, −0.008)***−0.009 (−0.011, −0.007)*** Subgroup analyses Sex Men−0.011 (−0.014, −0.007)***−0.011 (−0.015, −0.008)***−0.010 (−0.014, −0.007)***−0.009 (−0.013, −0.005)*** Women−0.012 (−0.014, −0.010)***−0.011 (−0.013, −0.008)***−0.009 (−0.011, −0.007)***−0.009 (−0.011, −0.006)***Age category 45–59 y−0.009 (−0.012, −0.006)***−0.008 (−0.011, −0.005)***−0.006 (−0.010, −0.003)***−0.006 (−0.009, −0.003)*** 60–74 y−0.010 (−0.014, −0.007)***−0.011 (−0.014, −0.007)***−0.010 (−0.014, −0.006)***−0.008 (−0.012, −0.005)*** 75+ y−0.014 (−0.018, −0.010)***−0.014 (−0.018, −0.010)***−0.013 (−0.017, −0.008)***−0.012 (−0.017, −0.007)***BMI category b  Underweight−0.028 (−0.044, −0.011)**−0.026 (−0.044, −0.009)**-- h −0.032 (−0.051, −0.012)** Normal weight−0.013 (−0.017, −0.010)***−0.012 (−0.016, −0.009)***-- h −0.011 (−0.015, −0.007)*** Overweight−0.008 (−0.011, −0.005)***−0.007 (−0.011, −0.004)***-- h −0.006 (−0.010, −0.003)** Obese−0.009 (−0.013, −0.004)***−0.009 (−0.013, −0.005)***-- h −0.008 (−0.013, −0.004)***MVPA category c  <150 min/week−0.011 (−0.015, −0.007)***−0.011 (−0.016, −0.006)***−0.009 (−0.014, −0.004)***-- i  150–299 min/week−0.007 (−0.012, −0.002)**−0.007 (−0.012, −0.002)**−0.007 (−0.013, −0.001)*-- i  >300 min/week−0.010 (−0.013, −0.007)***−0.010 (−0.012, −0.007)***−0.09 (−0.011, −0.006)***-- i Note : BMI = Body mass index; MVPA = Moderate- to vigorous-intensity physical activity. a Physical function was measured using the 10-item Medical Outcomes Study Physical Functioning Scale (MOS-PF) (35), a scale from 0 to 100 (with higher values representing better function). b Body mass index (BMI) was calculated from self-reported height and weight and categorized as: underweight (<18.5 kg/m 2 ), normal weight (≥18.5 kg/m 2  to <25 kg/m 2 ), overweight (≥25 kg/m 2  to <30 kg/m 2 ), and obese (≥30 kg/m 2 ). c Moderate-to-vigorous physical activity (MVPA) was measured using the Active Australia questionnaire (37). d Model 1: Adjusted for baseline MOS-PF score and follow-up time only. e Model 2: Adjusted for variables in Model 1+ age, sex, marital status, educational attainment, location of residence, living situation, and smoking. f  Model 3: Adjusted for variables in Model 2 + BMI category. g Model 4: Adjusted for variables in Model 3 + MVPA category. h The variable of BMI category was omitted from the model and therefore Model 3 was identical to Model 2. i The variable of MVPA category was omitted from the model and therefore Model 4 was identical to Model 3.*  p  < .05; **  p  < .01; ***  p  < .001; Effect modification by BMI category reached statistical significance at  p  < .05. Journals of Gerontology: MEDICAL SCIENCES,  2018, Vol. 00, No. 00 5 Downloaded from https://academic.oup.com/biomedgerontology/advance-article-abstract/doi/10.1093/gerona/gly008/4834950by Australian Catholic University useron 26 February 2018
Recommended
View more...
We Need Your Support
Thank you for visiting our website and your interest in our free products and services. We are nonprofit website to share and download documents. To the running of this website, we need your help to support us.

Thanks to everyone for your continued support.

No, Thanks
SAVE OUR EARTH

We need your sign to support Project to invent "SMART AND CONTROLLABLE REFLECTIVE BALLOONS" to cover the Sun and Save Our Earth.

More details...

Sign Now!

We are very appreciated for your Prompt Action!

x