Sitting time and depression in young women over 12-years: The effect of physical activity.

OBJECTIVES: Lack of physical activity (PA) and prolonged sitting time (ST) are associated with increased risk of mortality and chronic illnesses, including depression. While there have been claims that the two risks are 'independent', their joint and stratified effects are unclear. The aim of this study was to explore the combined effects of physical activity and sitting time on the 12year risk of depressive symptoms (DS) in young women. DESIGN: Cohort-9061 young participants in the Australian Longitudinal Study on Women's Health completed triennial surveys from 2000 (age 22-27), to 2012. METHODS: Generalised Estimating Equation models were used to calculate the joint effects of PA and ST on DS, with <4h/day of ST and the highest PA quartile as the reference categories. Relationships between PA and DS, and between ST and DS, were also examined after stratification by ST and PA respectively. RESULTS: In the adjusted joint effects model, compared with the reference category (low sitting, high PA), odds for DS were significantly higher in women who sat for >4, 6 and 8h/day and reported doing no PA. In every physical activity category, women who sat for ≥10h/day were at highest risk of DS (OR for lowest physical activity quartile, 1.72 [95% CI=1.38-2.14]; OR for highest physical activity quartile, 1.49 [95% CI=1.16-1.91]). After stratification by ST, odds of DS were reduced in women who reported any physical activity (compared with none), except when ST was >10h/day. After stratification by physical activity, the increased risk of sitting 8-10h/day was attenuated by any physical activity, but there was no reduction in risk of depressive symptoms with increasing PA levels in women who sat for ≥10h per day. CONCLUSIONS: These data suggest that there are both joint and stratified effects of too little activity and too much sitting on the risk of depressive symptoms in young women. High levels of PA are protective against the hazards of high ST at this life stage, except in women with very high levels of sitting.

Nine year changes in sitting time in young and mid-aged Australian women: findings from the Australian Longitudinal Study for Women's Health.

OBJECTIVE: To examine changes in sitting time (ST) in women over nine years and to identify associations between life events and these changes. METHODS: Young (born 1973-78, n=5215) and mid-aged (born 1946-51, n=6973) women reported life events and ST in four surveys of the Australian Longitudinal Study on Women's Health between 2000 and 2010. Associations between life events and changes in ST between surveys (decreasers ≥2 h/day less, increasers ≥2 h/day more) were estimated using generalized estimating equations. RESULTS: Against a background of complex changes there was an overall decrease in ST in young women (median change -0.48 h/day, interquartile range [IQR]=-2.54, 1.50) and an increase in ST in mid-aged women (median change 0.43 h/day; IQR=-1.29, 2.0) over nine years. In young women, returning to study and job loss were associated with increased ST, while having a baby, beginning work and decreased income were associated with decreased ST. In mid-aged women, changes at work were associated with increased ST, while retiring and decreased income were associated with decreased ST. CONCLUSIONS: ST changed over nine years in young and mid-aged Australian women. The life events they experienced, particularly events related to work and family, were associated with these changes.

The clinical effectiveness and cost-effectiveness of exercise referral schemes: a systematic review and economic evaluation.

BACKGROUND: Exercise referral schemes (ERS) aim to identify inactive adults in the primary-care setting. The GP or health-care professional then refers the patient to a third-party service, with this service taking responsibility for prescribing and monitoring an exercise programme tailored to the needs of the individual. OBJECTIVE: To assess the clinical effectiveness and cost-effectiveness of ERS for people with a diagnosed medical condition known to benefit from physical activity (PA). The scope of this report was broadened to consider individuals without a diagnosed condition who are sedentary. DATA SOURCES: MEDLINE; EMBASE; PsycINFO; The Cochrane Library, ISI Web of Science; SPORTDiscus and ongoing trial registries were searched (from 1990 to October 2009) and included study references were checked. METHODS: Systematic reviews: the effectiveness of ERS, predictors of ERS uptake and adherence, and the cost-effectiveness of ERS; and the development of a decision-analytic economic model to assess cost-effectiveness of ERS. RESULTS: Seven randomised controlled trials (UK, n = 5; non-UK, n = 2) met the effectiveness inclusion criteria, five comparing ERS with usual care, two compared ERS with an alternative PA intervention, and one to an ERS plus a self-determination theory (SDT) intervention. In intention-to-treat analysis, compared with usual care, there was weak evidence of an increase in the number of ERS participants who achieved a self-reported 90-150 minutes of at least moderate-intensity PA per week at 6-12 months' follow-up [pooled relative risk (RR) 1.11, 95% confidence interval 0.99 to 1.25]. There was no consistent evidence of a difference between ERS and usual care in the duration of moderate/vigorous intensity and total PA or other outcomes, for example physical fitness, serum lipids, health-related quality of life (HRQoL). There was no between-group difference in outcomes between ERS and alternative PA interventions or ERS plus a SDT intervention. None of the included trials separately reported outcomes in individuals with medical diagnoses. Fourteen observational studies and five randomised controlled trials provided a numerical assessment of ERS uptake and adherence (UK, n = 16; non-UK, n = 3). Women and older people were more likely to take up ERS but women, when compared with men, were less likely to adhere. The four previous economic evaluations identified suggest ERS to be a cost-effective intervention. Indicative incremental cost per quality-adjusted life-year (QALY) estimates for ERS for various scenarios were based on a de novo model-based economic evaluation. Compared with usual care, the mean incremental cost for ERS was £169 and the mean incremental QALY was 0.008, with the base-case incremental cost-effectiveness ratio at £20,876 per QALY in sedentary people without a medical condition and a cost per QALY of £14,618 in sedentary obese individuals, £12,834 in sedentary hypertensive patients, and £8414 for sedentary individuals with depression. Estimates of cost-effectiveness were highly sensitive to plausible variations in the RR for change in PA and cost of ERS. LIMITATIONS: We found very limited evidence of the effectiveness of ERS. The estimates of the cost-effectiveness of ERS are based on a simple analytical framework. The economic evaluation reports small differences in costs and effects, and findings highlight the wide range of uncertainty associated with the estimates of effectiveness and the impact of effectiveness on HRQoL. No data were identified as part of the effectiveness review to allow for adjustment of the effect of ERS in different populations. CONCLUSIONS: There remains considerable uncertainty as to the effectiveness of ERS for increasing activity, fitness or health indicators or whether they are an efficient use of resources in sedentary people without a medical diagnosis. We failed to identify any trial-based evidence of the effectiveness of ERS in those with a medical diagnosis. Future work should include randomised controlled trials assessing the cinical effectiveness and cost-effectivenesss of ERS in disease groups that may benefit from PA. FUNDING: The National Institute for Health Research Health Technology Assessment programme.

Effect of exercise referral schemes in primary care on physical activity and improving health outcomes: systematic review and meta-analysis.

OBJECTIVE: To assess the impact of exercise referral schemes on physical activity and health outcomes. Design Systematic review and meta-analysis. DATA SOURCES: Medline, Embase, PsycINFO, Cochrane Library, ISI Web of Science, SPORTDiscus, and ongoing trial registries up to October 2009. We also checked study references. Study selection Design: randomised controlled trials or non-randomised controlled (cluster or individual) studies published in peer review journals. POPULATION: sedentary individuals with or without medical diagnosis. Exercise referral schemes defined as: clear referrals by primary care professionals to third party service providers to increase physical activity or exercise, physical activity or exercise programmes tailored to individuals, and initial assessment and monitoring throughout programmes. Comparators: usual care, no intervention, or alternative exercise referral schemes. RESULTS: Eight randomised controlled trials met the inclusion criteria, comparing exercise referral schemes with usual care (six trials), alternative physical activity intervention (two), and an exercise referral scheme plus a self determination theory intervention (one). Compared with usual care, follow-up data for exercise referral schemes showed an increased number of participants who achieved 90-150 minutes of physical activity of at least moderate intensity per week (pooled relative risk 1.16, 95% confidence intervals 1.03 to 1.30) and a reduced level of depression (pooled standardised mean difference -0.82, -1.28 to -0.35). Evidence of a between group difference in physical activity of moderate or vigorous intensity or in other health outcomes was inconsistent at follow-up. We did not find any difference in outcomes between exercise referral schemes and the other two comparator groups. None of the included trials separately reported outcomes in individuals with specific medical diagnoses. Substantial heterogeneity in the quality and nature of the exercise referral schemes across studies might have contributed to the inconsistency in outcome findings. Conclusions Considerable uncertainty remains as to the effectiveness of exercise referral schemes for increasing physical activity, fitness, or health indicators, or whether they are an efficient use of resources for sedentary people with or without a medical diagnosis.