Patterns and predictors of sitting time over ten years in a large population-based Canadian sample: Findings from the Canadian Multicentre Osteoporosis Study (CaMos)

Bone health and prevalent fractures in women with polycystic ovary syndrome: a meta-analysis and endocrine-context pathophysiology review

INTRODUCTION

Bone health in those with Polycystic Ovary Syndrome (PCOS) is complex, but the general consensus is that cortical areal bone mineral density (aBMD) sites will be higher in PCOS than in age- and BMI-similar controls. However, spine aBMD sites may be lower, especially in non-obese PCOS. Whether or not incident fracture risk is increased in PCOS is currently controversial; no meta-analysis has yet assessed prevalent fractures.

AREAS COVERED

We assessed the bone effects of PCOS-related ovarian hormone alterations, e.g. androgen excess, tonically normal/higher estradiol, and lower-than-normal progesterone levels. We also highlighted evidence that common PCOS medications (e.g. combined hormonal contraceptives [CHC], metformin, and spironolactone) have important bone effects. In adolescents, meta-analysis of CHC showed significant negative aBMD changes. Inflammation has negative PCOS bone effects and is linked with CHC use.

EXPERT OPINION

Is fracture risk altered by PCOS? Our meta-analysis showed a 25% increased risk of prevalent fracture in PCOS versus controls; this did not reach statistical significance. Future prospective research needs to collect and evaluate ovulation characteristics, progesterone exposure, and adolescent CHC use, in addition to the complex variables that may influence risks for prevalent or incident fragility fractures and/or for cortical and cancellous aBMD values in PCOS.

Sedentary behaviour surveillance in Canada: trends, challenges and lessons learned

Background

Historical changes in the nature of sedentary activities have been observed in other countries, but it is not clear if similar trends exist in Canada. It is also unclear how changes in the measurement of sedentary behaviour affects national estimates. Our objective is to document all sources and measures of sedentary behaviour from Canadian, nationally representative surveys, and report on selected estimates of time spent in sedentary activities. Lessons learned can benefit the wider international surveillance community.

Methods

We describe and document all data sources of sedentary behaviour at the national level in Canada, and report on selected prevalence data from repeated cross-sectional surveys. We summarize amounts of total device-assessed sedentary time and self-reported sedentary activities (e.g., passive travel, leisure television, computer, video games, screen, and reading) by age group over time.

Results

Nineteen national surveys were identified. Changes in questions and/or response categories precluded direct assessment of trends over time for some measures; however, certain trends were observed. Accelerometer-measured sedentary time, leisure reading (among those < 50 years) and television/video viewing in younger age groups have remained relatively stable (with a possible slight decline in television/video viewing). Time spent in passive travel and leisure computer and electronic device use appears to have increased. Television and video viewing appears to have increased in older adults while their leisure reading appears to have fallen.

Conclusions

Changes in measurement of sedentary behaviour can affect estimates and reduce comparability over time. Total leisure screen use appears to have increased over time, reflecting the ways in which Canadians spend their free time and technological advances. The main public health message is the need for continued efforts to reduce leisure screen use, especially among youth and older adults.

Sedentary behavior in the city of São Paulo, Brazil: ISA-Capital 2015

INTRODUCTION

The excessive sitting time involved in activities of low energy expenditure (sedentary behavior) can contribute to the development of chronic diseases. Assessing factors related to this behavior in a population is important to identify its most vulnerable segments.

OBJECTIVE

To describe sitting time distribution in the adult population of São Paulo City according to sociodemographic and environmental characteristics and health conditions.

METHODS

This is a cross-sectional study involving 2,512 individuals, aged 20 to 65 years, who participated in the Health Survey in the City of São Paulo (Inquérito de Saúde no Município de São Paulo - ISA-Capital) 2015. Data relating to sitting time were collected using the International Physical Activity Questionnaire (IPAQ), initially analyzed continuously, and, afterward, dichotomized by the median to analyze categorical variables.

RESULTS

The total sitting time median in the sample was 180 min/day. The variables that, after adjustments, remained related to sedentary behavior were: schooling (prevalence ratio - PR = 1.41; 95% confidence interval - 95%CI 1.35 - 1.48); marital status (PR = 1.05; 95%CI 1.02 - 1.08); neighborhood safety (PR = 0.96; 95%CI 0.93 - 0.99); age (PR = 0.91; 95%CI 0.87 - 0.95); income (PR = 1.07; 95%CI 1.00 - 1.15); self-rated health (PR = 1.03; 95%CI 1.01 - 1.07), and gender (PR = 0.96; 95%CI 0.94 - 0.99).

CONCLUSION

The most vulnerable groups to sedentary behavior in this population are: younger males, with higher schooling and income, who live in neighborhoods considered safe, unmarried, and with negative self-rated health.

Stand Up, Students! Decisional Cues Reduce Sedentary Behavior in University Students

Background: University students are prone to sedentary behavior (SB) which is associated with multiple negative health outcomes. Sit-stand desks may allow for a reduction of SB through standing bouts. To promote standing in university students, decisional cues might be a low-cost approach that can easily be implemented. Purpose: To investigate the effects of decisional cues on students' SB, standing, and active behavior. Method: Over 3 weeks, students were observed in a building on a German university campus, which provides sit-stand-desks in study areas, using an adapted version of the SOPLAY protocol. Baseline data was collected in the first week (T1), before posters and table plaques containing decisional cues were set up in the study areas. Effects were measured in the following 2 weeks (T2 and T3). Results: 2,809 (33% female) students were observed. Sitting decreased from 92.9% [SD = 14.9] to 84.5% [SD = 22.1] from T1 to T3 [F (1, 141) = 15.6; p < 0.01; η2 = 0.10]. Standing increased from 5.6% [SD = 13.5] to 10.9% [SD = 14.4] [F (1, 141) = 9.0; p < 0.01; η2 = 0.06] and being active from 1.5% [SD = 6.9] to 4.5% [SD = 14.8] from T1 to T3 [F (1, 141) = 4.2; p < 0.05; η2 = 0.03). Main effect analyses revealed more students standing in the afternoon compared to morning and lunchtime [F (2, 140) = 3.2; p < 0.05; η2 = 0.04). Discussion: Decisional cues could decrease students' SB and promote standing or being active as alternatives. Future research should use a more rigorous study design. The content of the decisional cues should be explored more and expanded to other health promotion areas on campus.

Long-term determinants of changes in television viewing time in adults: Prospective analyses from the Young Finns Study

PURPOSE

The long-term effects of sociodemographic and health characteristics on television viewing (TV) time changes have not been identified in adulthood. We aimed to examine the modifiable and non-modifiable determinants of changes in TV-time in young adults over 10 years.

METHODS

Participants (N = 2929) aged 24-39 years were recruited between 2001 and 2011 from the Cardiovascular Risk in Young Finns Study. Data were collected using questionnaires and a medical examination. The determinants of changes in TV-time were estimated using latent growth modeling for men and women separately.

RESULTS

For men, inverse associations with initial levels of TV-time were observed for students becoming employed and already has children, and direct associations were observed for both those who stayed a smoker and those who stayed overweight/obese. Increasing attention to health habits was inversely associated with a slope of TV-time, whereas age and becoming unemployed were positively associated with the slope of TV-time. For women, inverse associations with the levels of TV-time were found for age, staying in non-manual work, and paying consistently high and increasing attention to health habits, and direct associations were found for staying unemployed, smoking and overweight/obese, and becoming employed, single and non-smoking. Increasing physical activity, becoming employed, motherhood, and normal weight were inversely associated with the slope of TV-time, whereas age and staying in non-manual work were positively associated with the slope of TV-time.

CONCLUSIONS

This suggests several gender-specific determinants of changes in TV-time that can help identify potential targets for interventions to prevent excessive TV-time in adulthood.

Implications of parental lifestyle changes and education level on adolescent offspring weight: a population based cohort study - The HUNT Study, Norway

OBJECTIVE

Obesity tends to cluster in families reflecting both common genetics and shared lifestyle patterns within the family environment. The aim of this study was to examine whether parental lifestyle changes over time, exemplified by changes in weight and physical activity, could affect offspring weight in adolescents and if parental education level influenced the relationship.

DESIGN, SETTING AND PARTICIPANTS

The population-based cohort study included 4424 parent-offspring participants from the Nord-Trøndelag Health Study, Norway. Exposition was parental change in weight and physical activity over 11 years, and outcome was offspring weight measured in z-scores of body mass index (BMI) in mixed linear models.

RESULTS

Maternal weight reduction by 2-6 kg was significantly associated with lower offspring BMI z-scores: -0.132 (95% CI -0.259 to -0.004) in the model adjusted for education. Parental weight change displayed similar effect patterns on offspring weight regardless of parents' education level. Further, BMI was consistently lower in families of high education compared with low education in the fully adjusted models. In mothers, reduced physical activity level over time was associated with higher BMI z-scores in offspring: 0.159 (95% CI 0.030 to 0.288). Associations between physical activity change and adolescent BMI was not moderated by parental education levels.

CONCLUSION

Lifestyle changes in mothers were associated with offspring BMI; reduced weight with lower-and reduced physical activity with higher BMI. Father's lifestyle changes, however, did not significantly affect adolescent offspring's weight. Overall, patterns of association between parental changes and offspring's BMI were independent of parental education levels, though adolescents with parents with high education had lower weight in general.

Progesterone for the prevention and treatment of osteoporosis in women

Estradiol (E2) is women's dominant 'bone hormone' since it is essential for development of adolescent peak bone mineral density (BMD) and physiological levels prevent the rapid (3-week) bone resorption that causes most adult BMD loss. However, deceasing E2 levels trigger bone resorption/loss. Progesterone (P4) is E2's physiological partner, collaborating with E2 in every cell/tissue; its bone 'job' is to increase P4-receptor-mediated, slow (3-4 months) osteoblastic new bone formation. When menstrual cycles are normal length and normally ovulatory, E2 and P4 are balanced and BMD is stable. However, clinically normal cycles commonly have ovulatory disturbances (anovulation, short luteal phases) and low P4 levels; these are more frequent in teen and perimenopausal women and increased by everyday stressors: energy insufficiency, emotional/social/economic threats and illness. Meta-analysis shows that almost 1%/year spinal BMD loss occurs in those with greater than median (∼31%) of ovulatory disturbed cycles. Prevention of osteoporosis and fragility fractures requires the reversal of stressors, detection and treatment of teen-to-perimenopausal recurrent cycle/ovulatory disturbances with cyclic oral micronized progesterone. Low 'Peak Perimenopausal BMD' is likely the primary risk for fragility fractures in later life. Progesterone plus estradiol or other antiresorptive therapies adds 0.68%/year and may be a highly effective osteoporosis treatment. Randomized controlled trials are still needed to confirm progesterone's important role in women's bone formation.

Recent trends in population levels and correlates of occupational and leisure sitting time in full-time employed Australian adults

This study aimed to explore the trend in population levels, as well as the correlates, of occupational and leisure sitting time in full-time employed Australian adults between 2007 and 2015. We used data from the 2007/08, 2011/12 and 2014/15 Australian Health Surveys, in which nationally representative samples of the Australian population were interviewed. Full-time (≥35 hours/week) employed respondents reported sitting time at work and during leisure on a usual workday. Trends over time and associations between socio-demographic and health-related characteristics and sitting time were analysed in the combined dataset using multivariable logistic regression models. Over 21,000 observations were included in the analyses. Across the three surveys, approximately 51% of the respondents reported ≥4 hours/workday occupational sitting time, 40% reported ≥4 hours/workday leisure sitting time, and 55% reported ≥7 hours/workday combined occupational and leisure sitting time. There were no clear trends over time. All potential correlates were associated with occupational sitting time and all but educational level were associated with leisure sitting time. The directions of the associations with gender, age and leisure-time physical activity were reversed for occupational sitting time and leisure sitting time. These findings show that the average levels of occupational and leisure sitting time on workdays were high but stable over the past decade. The observed differences in correlates of occupational and leisure sitting time demonstrate the need to assess and address sedentary behaviour domains separately in research and policy.