Statistical approaches to testing the relationships of the built environment with resident-level physical activity behavior and health outcomes in cross-sectional studies with cluster sampling

To achieve valid conclusions, studies exploring associations of the built environment with residents' physical activity and health-related outcomes need to employ statistical approaches accounting for clustered data. This article discusses the following main statistical approaches: analysis of covariance, regression models with robust standard errors, generalized estimating equations, and multilevel generalized linear models. The choice of a statistical method depends on the characteristics of the study and research questions. While the first three approaches are employed to account for clustering in the data, multilevel models can also help unravel more substantive issues within a social ecological theoretical framework of health behavior.

A meta-analysis of cross sectional studies investigating language in maltreated children

Purpose: In this review article, meta-analysis was used to summarize research investigating language skills in maltreated children. Method: A systematic search of published studies was undertaken. Studies were included in the meta-analysis if they investigated language skills in groups comprising maltreated and nonmaltreated children. Studies were selected if these 2 groups of children were of comparable age and from a similar socioeconomic background. Results: A total of 26 studies were identified that met the inclusion criteria. Results from the meta-analysis showed that maltreated children demonstrated consistently poorer language skills with respect to receptive vocabulary (k = 19; standardized mean difference [SMD] = .463; 95% confidence interval [CI; .293, .634]; p < .001), expressive language (k = 4; SMD =.860; 95% CI [.557, 1.163]; p < .001), and receptive language (k = 9; SMD =.528; 95% CI [.220, .837]; p < .001). Conclusion: Together, these results indicate a reliable association between child maltreatment and poor language skills.

Australian children's independent mobility levels: secondary analyses of cross-sectional data between 1991 and 2012

This study investigated changes in Australian children's independent mobility levels between1991 and 2012. Data from five cross-sectional studies conducted in 1991, 1993, 2010, 2011 and 2012 were analysed. Parent and child surveys were used to assess parental licences for independent mobility and actual independent mobility behaviour in children aged 8–13 years. Findings show declines in the proportion of young children (≤10 years of age) being allowed to travel home from school alone (1991: 68%, 1993: 50%, 2010: 43%, 2011: 45%, 2012: 31%) and travel on buses alone (1991: 31%, 1993: 15%, 2010: 8%, 2011: 6%, 2012: 9%). Furthermore, the proportion of children travelling independently to school decreased (1991: 61%, 1993: 42%, 2010: 31%, 2011: 32%, 2012: 32%). Significantly fewer girls than boys travelled independently to school at each time point (p ≤ .001). Overall, the findings suggest that Australian children's independent mobility levels declined between 1991 and 2012.

Morbidity patterns among the underweight, overweight and obese between 2 and 18 years: population-based cross-sectional analyses

CONTEXT: No study has documented how symptomatic morbidity varies across the body mass index (BMI) spectrum (underweight, normal weight, overweight and obese) or across the entire child and adolescent age range. OBJECTIVE: To (1) quantify physical and psychosocial morbidities experienced by 2-18-year-olds according to BMI status and (2) explore morbidity patterns by age. DESIGN, SETTING AND PARTICIPANTS: Cross-sectional data from two Australian population studies (the Longitudinal Study of Australian Children and the Health of Young Victorians Study) were collected during 2000-2006. Participants were grouped into five age bands: 2-3 (n=4606), 4-5 (n=4983), 6-7 (n=4464), 8-12 (n=1541) and 13-18 (n=928) years. MAIN MEASURES: Outcomes-Parent- and self-reported global health; physical, psychosocial and mental health; special health-care needs; wheeze; asthma and sleep problems. Exposure-measured BMI (kg m(-2)) categorised using standard international cutpoints. ANALYSES: The variation in comorbidities across BMI categories within and between age bands was examined using linear and logistic regression models. RESULTS: Comorbidities varied with BMI category for all except sleep problems, generally showing the highest levels for the obese category. However, patterns differed markedly between age groups. In particular, poorer global health and special health-care needs were associated with underweight in young children, but obesity in older children. Prevalence of poorer physical health varied little by BMI in 2-5-year-olds, but from 6 to 7 years was increasingly associated with obesity. Normal-weight children tended to experience the best psychosocial and mental health, with little evidence that the U-shaped associations of these variables with BMI status varied by age. Wheeze and asthma increased slightly with BMI at all ages. CONCLUSIONS: Deviation from normal weight is associated with health differences in children and adolescents that vary by morbidity and age. As well as lowering risks for later disease, promoting normal body weight appears central to improving the health and well-being of the young.

Physical activity guidelines and cardiovascular risk in children: a cross sectional analysis to determine whether 60 minutes is enough

BACKGROUND: Physical activity reduces cardiovascular mortality and morbidity. The World Health Organisation (WHO) recommends children engage in 60 min daily moderate-to-vigorous physical activity (MVPA). The effect of compliance with this recommendation on childhood cardiovascular risk has not been empirically tested. To evaluate whether achieving recommendations results in reduced composite-cardiovascular risk score (CCVR) in children, and to examine if vigorous PA (VPA) has independent risk-reduction effects.

METHODS: PA was measured using accelerometry in 182 children (9-11 years). Subjects were grouped according to achievement of 60 min daily MVPA (active) or not (inactive). CCVR was calculated (sum of z-scores: DXA body fat %, blood pressure, VO2peak, flow mediated dilation, left ventricular diastolic function; CVR score ≥ 1SD indicated 'higher risk'). The cohort was further split into quintiles for VPA and odds ratios (OR) calculated for each quintile.

RESULTS: Active children (92 (53 boys)) undertook more MVPA (38 ± 11 min, P < 0.001), had greater VO2peak (4.5 ± 0.8 ml/kg/min P < 0.001), and lower fat % (3.9 ± 1.1 %, P < 0.001) than inactive. No difference were observed between active and inactive for CCVR or OR (P > 0.05). CCVR in the lowest VPA quintile was significantly greater than the highest quintile (3.9 ± 0.6, P < 0.05), and the OR was 4.7 times higher.

CONCLUSION: Achievement of current guidelines has positive effects on body composition and cardiorespiratory fitness, but not CCVR. Vigorous physical activity appears to have beneficial effects on CVD risk, independent of moderate PA, implying a more prescriptive approach may be needed for future VPA guidelines.

Renal access coordinators' impact on hemodialysis patient outcomes and associated service delivery: a systematic review

Background
Renal access coordinators contribute specifically to dialysis access care for people with chronic and end stage renal disease. Since the introduction of renal access coordinators into Australia in the early 2000s, there have been anecdotal examples of associated improvements in patient outcomes and service delivery; however scant published quantitative evidence exists. Thus, the impact of the implementation of renal access coordinators has not undergone a rigorous review to date.

Objective
The objective of this systematic review was to critically appraise and synthesize the best available evidence related to the impact of renal access coordinators on dialysis patient outcomes and associated service delivery.

INCLUSION CRITERIA

Types of participants
This review considered studies that included renal access coordinators (noting variations of the titles) and adult hemodialysis patients (aged 18 years and over).

Types of intervention(s)
This review considered studies that evaluated the effectiveness of the renal access coordinator. This role typically consists of clinical and administration duties such as providing pre dialysis access coordination, access surveillance patient education and nurse education.

Types of studies
The types of studies considered within this review included experimental and epidemiological study designs. Thus randomized controlled trials (RCT), non-randomized controlled trials, and quasi-experimental, before and after studies, prospective and retrospective cohort studies were considered as were case control studies, analytical cross sectional studies and descriptive cross sectional studies.

Types of outcomes
Patient outcomes considered included: days to first vascular access complication (such as stenosis or thrombosis) and/or primary intervention (such as angioplasty or surgical intervention); percentage of central line insertions (negative); rate of arteriovenous fistula (AVF)/arteriovenous graft (AVG)/central venous catheter (CVC) at start of dialysis (incidence); prevalent rate of AVF/AVG/CVC; time to occlusion of AVF and time from referral to surgery. Service outcomes included: knowledge/up skilling of renal nurses; cannulation skills, ultrasound skills, knowledge of anatomy and physiology and other access related knowledge.

Search strategy
The search strategy aimed to locate published and unpublished studies, utilizing a three-step searching approach. Studies published in English from 1990 to October 2013 were considered for inclusion in this review.

Methodological quality
The studies were assessed by two independent reviewers using the appropriate standardized critical appraisal instruments from the Joanna Briggs Institute.

Data collection
Data were extracted from papers included in the review using the standardised data extraction tool from the Joanna Briggs Institute, namely JBI Meta-Analysis of Statistics Assessment and Review Instrument (JBI-MAStARI).

Data synthesis
This review aimed to conduct meta-analyses of the findings: however, because of the limitations of the data found, this was not possible and so the findings are presented in a narrative format.

Results
Five studies were identified for inclusion in the review. No RCTs were found, therefore four of the five studies were pre-post intervention cohort studies and one was a prospective quality assurance report. Data were heterogeneous and thus did not allow for meta-analysis. All studies included multidisciplinary teams with variable emphasis on the renal access coordinator role. The pre post intervention cohort studies measured incident and/or prevalent AVF, AVG and CVC rates in the hemodialysis population and the quality assurance report measured the difference in patency rates between AVF and AVG. All discussed the role of central coordination as a contributor to the success of vascular access care.

Conclusions
This review found insufficient data to make firm conclusions about the impact that renal access coordinators have on patient outcomes. The results of this review suggest an association between renal access coordinators and improved patient outcomes. These improved patient outcomes were apparent in an increase in incident and prevalent AVFs, and a decrease in the incidence and prevalence of CVCs. Both associations are correlated with a reduction in infection rates, length of hospital stay and healthcare costs.

Takeaway food consumption and its associations with diet quality and abdominal obesity : a cross-sectional study of young adults

Background : Few studies have investigated the associations of takeaway food consumption with overall diet quality and abdominal obesity. Young adults are high consumers of takeaway food so we aimed to examine these associations in a national study of young Australian adults.

Methods : A national sample of 1,277 men and 1,585 women aged 26–36 completed a self-administered questionnaire on demographic and lifestyle factors, a 127 item food frequency questionnaire, usual daily frequency of fruit and vegetable consumption and usual weekly frequency of takeaway food consumption. Dietary intake was compared with the dietary recommendations from the Australian Guide to Healthy Eating. Waist circumference was measured for 1,065 men and 1,129 women. Moderate abdominal obesity was defined as ≥ 94 cm for men and ≥ 80 cm for women. Prevalence ratios (PR) were calculated using log binomial regression. Takeaway food consumption was dichotomised, with once a week or less as the reference group.

Results : Consumption of takeaway food twice a week or more was reported by more men (37.9%) than women (17.7%, P < 0.001). Compared with those eating takeaway once a week or less, men eating takeaway twice a week or more were significantly more likely to be single, younger, current smokers and spend more time watching TV and sitting, whereas women were more likely to be in the workforce and spend more time watching TV and sitting. Participants eating takeaway food at least twice a week were less likely (P < 0.05) to meet the dietary recommendation for vegetables, fruit, dairy, extra foods, breads and cereals (men only), lean meat and alternatives (women only) and overall met significantly fewer dietary recommendations (P < 0.001). After adjusting for confounding variables (age, leisure time physical activity, TV viewing and employment status), consuming takeaway food twice a week or more was associated with a 31% higher prevalence of moderate abdominal obesity in men (PR: 1.31; 95% CI: 1.07, 1.61) and a 25% higher prevalence in women (PR: 1.25; 95% CI: 1.04, 1.50).

Conclusion : Eating takeaway food twice a week or more was associated with poorer diet quality and a higher prevalence of moderate abdominal obesity in young men and women.

Contrasting longitudinal and cross-sectional relationships between insulin resistance and percentage of body fat, fitness, and physical activity in children—the LOOK study

Background: Knowledge of individual changes in insulin resistance (IR) and longitudinal relationships of IR with lifestyle-associated factors are of important practical significance, but little longitudinal data exist in asymptomatic children. We aimed to determine (a) changes in the homeostatic model of insulin resistance (HOMA-IR) over a 2-yr period and (b) comparisons of longitudinal and cross-sectional relationships between HOMA-IR and lifestyle-related risk factors.

Methods: Our subjects, 241 boys and 257 girls, were assessed at age 8.1 yr (SD 0.35) and again 2 yr later for fasting blood glucose and insulin, dual X-ray absorptiometry-assessed percentage of body fat (%BF), pedometer-assessed physical activity (PA), and cardio-respiratory fitness (CRF) by multistage running test.

Results: HOMA-IR was initially 9% greater in girls than boys and 27% greater 2 yr later. There was no evidence of longitudinal relationships between HOMA-IR and %BF in boys or girls, despite significant cross-sectional relationships (p < 0.001). In boys, there was evidence of a longitudinal relationship between HOMA-IR and both PA (p < 0.001) and CRF (p = 0.05). In girls, we found a cross-sectional relationship between HOMA-IR and CRF (p < 0.001).

Conclusions: HOMA-IR increases between 8 and 10 yr of age and to a greater extent in girls. Longitudinal, unlike cross-sectional, relationships do not support the premise that body fat has any impact on HOMA-IR during this period or that PA or CRF changes affect HOMA-IR in girls. These data draw attention to difficulties in interpreting observational studies in young children.

Maternal correlates of preschool child eating behaviours and body mass index : a cross-sectional study

To the authors’ knowledge, this is the first study to evaluate maternal child feeding practices, maternal parenting characteristics and mother-child interactions as cross-sectional predictors of child eating and/or weight within the one sample. Maternal pressure for her child to eat was a significant positive correlate of fussiness and a negative correlate of enjoyment. Maternal parenting warmth was associated negatively with child BMIz, while mother-child dysfunctional interaction was associated positively with child BMIz. Our findings suggest that childhood obesity research may be better informed by evaluating not just what mothers do (feeding practices) but also how they parent (parenting behaviours and interactions with their child). Longitudinal studies are needed to identify causal influences of parenting on preschool child eating and weight.

On your bike! A cross-sectional study of the individual, social and environmental correlates of cycling to school

Background : Active school transport (AST) has declined rapidly in recent decades. While many studies have examined walking, cycling to school has received very little attention. Correlates of cycling are likely to differ to those from walking and cycling enables AST from further distances. This study examined individual, social and environmental factors associated with cycling to school among elementary school-aged children, stratified by gender.

Methods : Children (n = 1197) attending 25 Australian primary schools located in high or low walkable neighborhoods, completed a one-week travel diary and a parent/child questionnaire on travel habits and attitudes.

Results : Overall, 31.2% of boys and 14.6% of girls cycled ≥ 1 trip/week, however 59.4% of boys and 36.7% of girls reported cycling as their preferred school transport mode. In boys (but not girls), school neighborhood design was significantly associated with cycling: i.e., boys attending schools in neighborhoods with high connectivity and low traffic were 5.58 times more likely to cycle (95% CI 1.11-27.96) and for each kilometer boys lived from school the odds of cycling reduced by 0.70 (95% CI 0.63-0.99). Irrespective of gender, cycling to school was associated with parental confidence in their child's cycling ability (boys: OR 10.39; 95% CI 3.79-28.48; girls: OR 4.03; 95% CI 2.02-8.05), parental perceived convenience of driving (boys: OR 0.42; 95% CI 0.23-0.74; girls: OR 0.40; 95% CI 0.20-0.82); and child's preference to cycle (boys: OR 5.68; 95% CI 3.23-9.98; girls: OR 3.73; 95% CI 2.26-6.17).

Conclusion : School proximity, street network connectivity and traffic exposure in school neighborhoods was associated with boys (but not girls) cycling to school. Irrespective of gender, parents need to be confident in their child's cycling ability and must prioritize cycling over driving.

Gender differences in recreational and transport cycling : a cross-sectional mixed-methods comparison of cycling patterns, motivators, and constraints

Background
Gender differences in cycling are well-documented. However, most analyses of gender differences make broad comparisons, with few studies modeling male and female cycling patterns separately for recreational and transport cycling. This modeling is important, in order to improve our efforts to promote cycling to women and men in countries like Australia with low rates of transport cycling. The main aim of this study was to examine gender differences in cycling patterns and in motivators and constraints to cycling, separately for recreational and transport cycling.

Methods
Adult members of a Queensland, Australia, community bicycling organization completed an online survey about their cycling patterns; cycling purposes; and personal, social and perceived environmental motivators and constraints (47% response rate). Closed and open-end questions were completed. Using the quantitative data, multivariable linear, logistic and ordinal regression models were used to examine associations between gender and cycling patterns, motivators and constraints. The qualitative data were thematically analyzed to expand upon the quantitative findings.

Results
In this sample of 1862 bicyclists, men were more likely than women to cycle for recreation and for transport, and they cycled for longer. Most transport cycling was for commuting, with men more likely than women to commute by bicycle. Men were more likely to cycle on-road, and women off-road. However, most men and women did not prefer to cycle on-road without designed bicycle lanes, and qualitative data indicated a strong preference by men and women for bicycle-only off-road paths. Both genders reported personal factors (health and enjoyment related) as motivators for cycling, although women were more likely to agree that other personal, social and environmental factors were also motivating. The main constraints for both genders and both cycling purposes were perceived environmental factors related to traffic conditions, motorist aggression and safety. Women, however, reported more constraints, and were more likely to report as constraints other environmental factors and personal factors.

Conclusion
Differences found in men’s and women’s cycling patterns, motivators and constraints should be considered in efforts to promote cycling, particularly in efforts to increase cycling for transport.

Investigating well-being, work limitations and preferences for self-management education and peer support among younger people with hip and knee osteoarthritis: protocol for a cross-sectional study

Introduction: 

Relationship between overweight and health-related quality of life in secondary school children in Fiji: results from a cross-sectional population-based study

Objective
To investigate the relationship between excess weight (overweight and obesity) and health-related quality of life (HRQoL) in a sample of secondary school children in Fiji, by gender, age and ethnicity.

Methods
The study comprised 8947 children from forms 3–6 (age 12–18 years) in 18 secondary schools on Viti Levu, the main island of Fiji. Body mass index (BMI) was calculated from measured height and weight, and weight status was classified according to the International Obesity Task Force recommendations. HRQoL was measured by the self-report version of the Pediatric Quality of Life Inventory 4.0.

Results
HRQoL was similar in children with obesity and normal weight. Generally, this was replicated when analyzed separately by gender and ethnicity, but age stratification revealed disparities. In 12–14-year-old children, obesity was associated with better HRQoL, owing to better social and school functioning and well-being, and in 15–18-year olds with poorer HRQoL, owing to worse physical, emotional and social functioning and well-being (Cohen’s d 0.2–0.3). Children with a BMI in the overweight range also reported a slightly lower HRQoL than children with a BMI in the normal weight range, but although statistically significant, the size of this difference was trivial (Cohen’s d <0.2).

Discussion
The results suggest that, overall there is no meaningful negative association between excess weight and HRQoL in secondary school children in Fiji. This is in contradiction to the negative relationship between excess weight and HRQoL shown in studies from other countries and cultures. The assumption that a large body size is associated with a lower quality of life cannot be held universally. Although a generally low HRQoL among children in Fiji may be masking or overriding the potential effect of excess weight on HRQoL, socio-economic and/or socio-cultural factors, may help to explain these relationships.

Assessing mediators between discrimination, health behaviours and physical health outcomes: a representative cross-sectional study

PURPOSE: Discrimination is a social determinant of health; however, the pathways linking discrimination to ill-health are under-researched. This study investigated the mediators through which discrimination affects health behaviours and physical health outcomes, as well as assessed whether sex moderated these mechanisms. METHODS: Data from a representative survey (n = 1023) of undergraduate students enrolled in a Brazilian university in 2012 were used. Structural equation models were applied to assess the following mediation mechanisms--(1) discrimination influences self-rated health and body mass index via anxiety/depression; (2) discrimination affects behaviours (alcohol consumption, problem drinking, smoking, fruit/vegetable consumption, and physical activity) through discomfort associated with discriminatory experiences. The potential of sex to act as an effect-modifying variable was also explored in each of the postulated pathways. RESULTS: The effect of discrimination on self-rated poor health was totally (100.0%) mediated by anxiety/depression, while body mass index was not correlated with discrimination. Self-reported discrimination was associated with some behaviours via discomfort. Particularly, discomfort partially mediated the positive association between discrimination, leisure time physical activity (43.3%), and fruit/vegetable consumption (52.2%). Sex modified the association between discrimination, discomfort and physical activity in that such mechanism (more discrimination → more discomfort → more physical activity) was statistically significant in the entire sample and among females, but not among males. CONCLUSIONS: This is one of the first studies to demonstrate that discrimination is associated with physical health outcomes and behaviours via distinct pathways. Future investigations should further explicate the mediational pathways between discrimination and key health outcomes.