Differential association of cardiorespiratory fitness and central adiposity among US adolescents and adults: A quantile regression approach

Previous studies assessing the association between cardiorespiratory fitness (CRF) and waist circumference (WC) have often restricted their evaluation to the association of CRF on average WC. Consequently, the assessment of important variations in the relationship of CRF across the WC distribution was precluded. The purpose of this study was to comprehensively evaluate the association between CRF and the distribution of WC using quantile regression. Secondary data analysis was conducted using data from the 1999–2004 NHANES. Participants (n = 8260) aged 12–49 years with complete data on estimated maximal oxygen consumption and WC were included. Quantile regression models were performed to assess the association between CRF and the 10th, 25th, 50th, 75th and 90th WC percentiles and were adjusted for age and race/ethnicity. For male and female adolescents with high CRF compared to low-fit counterparts, significant negative estimates (2.8 to 20.2 cm and 2.3 to 11.2 cm, respectively) were observed across most WC percentiles. Similarly, among male and female adults, high CRF was associated with significant reductions in WC across all percentiles (9.5 to 12.0 cm and 3.7 to 9.2 cm, respectively). For both populations, an increasing trend in the magnitude of the association of high CRF across the WC percentiles was observed. CRF appears to have a differential relationship across the WC distribution with the largest reductions in WC were found among high-fit individuals with the greatest amount of central adiposity (WC ≥ 90th percentile). Additionally, this differential association highlights the significant limitations of statistical techniques used in previous analyses which focused on the center of the distribution.     

Obesity has few effects on future psychosocial functioning of adolescents

We reexamine the effects of obesity on a wide range (n = 17) of indicators of functioning drawn from five broad domains: interpersonal problems, psychological problems, suicidal behaviors, academic performance, and psychiatric disorders. Evidence on this question is mixed. Data are analyzed from a large community sample of adolescents 11–17 at baseline (n = 4175) who were followed up a year later (n = 3134). Using measured height and weight, overweight was defined as 95th > BMI ≤ 85th percentile and obese as BMI > 95th percentile. At baseline, obesity was associated with increased odds only for any mood disorder and poor perceived mental health. For boys, there were no significant associations, but girls had higher odds of problems at school, poor perceived mental health, and mood disorders. Results from the two-wave cohort reveal obesity increased future risk only for poor perceived mental health. For boys, the same pattern was observed, but for girls there were no significant associations. Overall, we found that weight status had few deleterious effects on adolescent social functioning, in multivariate, prospective analyses. If there is an effect of obesity on functioning, it may operate through mediators such as body image.     

Proximity to supermarkets associated with higher body mass index among overweight and obese preschool-age children

ObjectiveThe objective of this study is to examine associations of proximity to food establishments with body mass index (BMI) among preschool-age children.MethodsWe used baseline data from 438 children ages 2–6.9 years with a BMI ≥ 85th percentile participating in a RCT in Massachusetts from 2006 to 2009. We used a geographic information system to determine proximity to six types of food establishments: 1) convenience stores, 2) bakeries, coffee shops, candy stores, 3) full service restaurants, 4) large supermarkets, 5) small supermarkets, and 6) fast-food restaurants. The main outcome was child's BMI.ResultsChildren's mean (SD) BMI was 19.2 (2.4) kg/m²; 35% lived ≤ 1 mile from a large supermarket, 42% lived > 1 to 2 miles, and 22% lived > 2 miles. Compared to children living > 2 miles from a large supermarket, those who lived within 1 mile had a BMI 1.06 kg/m² higher. Adjustment for socioeconomic characteristics and distance to fast-food restaurants attenuated this estimate to 0.77 kg/m². Living in any other distance category from a large supermarket and proximity to other food establishments were not associated with child BMI.ConclusionsLiving closer to a large supermarket was associated with higher BMI among preschool-age children who were overweight or obese.     

Innovation to motivation—pilot study of a mobile phone intervention to increase physical activity among sedentary women

ObjectivesThis uncontrolled pilot study assessed changes in pedometer-measured step counts and self-reported physical activity during a 3-week mobile phone-based intervention. We also explored whether age, BMI, and psychosocial factors were associated with changes in step counts.MethodsForty-one sedentary adult women in San Francisco, California were asked to report their pedometer steps using a study-supplied mobile phone from June to September 2008. In the second and third weeks, daily prompts delivered by the mobile phone encouraged participants to increase steps by 20% from the previous week.ResultsMean age was 48 years. Average daily total steps increased by approximately 800 or 15% over three weeks (p < 0.001). Lower BMI, no antidepressant use, and lower self-reported health status were associated with higher step counts at baseline. Improvements in self-reported will-power were associated with increases in step counts (p < 0.001). Neither age (p = 0.55) nor BMI (p = 0.13) was significantly associated with changes in activity over the 3 weeks.ConclusionsThe intervention appeared to motivate sedentary women to increase their physical activity. A randomized controlled clinical trial is warranted and feasible.     

Longitudinal associations of active commuting with body mass index

ObjectiveTo investigate the longitudinal associations between active commuting (walking and cycling to work) and body mass index (BMI).MethodWe used self-reported data on height, weight and active commuting from the Commuting and Health in Cambridge study (2009 to 2012; n = 809). We used linear regression to test the associations between: a) maintenance of active commuting over one year and BMI at the end of that year; and b) change in weekly time spent in active commuting and change in BMI over one year.ResultsAfter adjusting for sociodemographic variables, other physical activity, physical wellbeing and maintenance of walking, those who maintained cycle commuting reported a lower BMI on average at one year follow-up (1.14 kg/m², 95% CI: 0.30 to 1.98, n = 579) than those who never cycled to work. No significant association remained after adjustment for baseline BMI. No significant associations were observed for maintenance of walking. An increase in walking was associated with a reduction in BMI (0.32 kg/m², 95% CI: 0.03 to 0.62, n = 651, after adjustment for co-variates and baseline BMI) only when restricting the analysis to those who did not move. No other significant associations between changes in weekly time spent walking or cycling on the commute and changes in BMI were observed.ConclusionsThis work provides further evidence of the contribution of active commuting, particularly cycling, to preventing weight gain or facilitating weight loss. The findings may be valuable for employees choosing how to commute and engaging employers in the promotion of active travel.     

Fat-free mass depletion in cystic fibrosis: Associated with lung disease severity but poorly detected by body mass index

ObjectiveMalnutrition in cystic fibrosis (CF) is associated with poorer survival, but the determinants of fat-free mass (FFM) depletion are not well-characterized. It is unknown whether routine nutritional indicators, including body mass index (BMI), are adequate for detecting FFM depletion. This study aimed to determine the prevalence of FFM depletion in adults with CF, to compare fat-free mass index (FFMI) with BMI, and to identify predictors of FFM depletion.MethodsThis was a prospective cross-sectional study of 86 adults with CF (19–59 y old). Body composition was assessed using dual-energy X-ray absorptiometry to determine FFMI and BMI. FFMI percentiles and Z-scores were derived from a reference population of 156 healthy adults. FFM depletion was defined as an FFMI below the fifth percentile for age and gender and low BMI as <18.5 kg/m². Univariate and multivariate analyses identified predictors of FFMI and FFMI Z-score.ResultsMean FFMIs were 18.3 ± 1.9 kg/m² in men with CF and 15.8 ± 1.1 kg/m² in women with CF (P < 0.0005). FFM depletion was found in 14% of adults with CF, and low BMI was found in 18.6%. The sensitivity of BMI for detecting FFM depletion was 42%. Forced expiratory volume in 1 s as a percentage of predicted was independently associated with FFMI in women (r = 0.62, P < 0.0001) and men (r = 0.28, P = 0.045) and FFMI Z-score (r = 0.41, P < 0.0001).ConclusionFFM depletion was found in 14% of adults with CF, but was undetectable by BMI in 58% of these patients. These findings, together with the association of FFMI with forced expiratory volume in 1 s predicted, suggest a role for body composition assessment in adult CF care.     

PCBs,PCDD/Fs,and PBDEs in blood samples of a rural population in South Germany

The body burden of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), dioxin-like (dl-PCBs) and non-dioxin-like (ndl-PCBs) polychlorinated biphenyls, and polybrominated diphenyl ethers (PBDEs) was determined in blood samples from 70 subjects between 4 and 76 years old. The participants of the study were recruited in the neighborhood of a reclamation plant located in a rural area in Southern Germany.The median concentrations (95th percentiles in parentheses), expressed as WHO₂₀₀₅-TEQ (toxic equivalents), for PCDD/Fs and dl-PCBs were 4.5 (17.9) pg g⁻¹ l.w. and 2.6 (13.2) pg g⁻¹ l.w., respectively. The dl-PCBs contributed 40% of the total TEQ (median values), and the most abundant congener was PCB 156. Combined, the sum of the 6 non-dioxin-like PCBs had a median of 0.773 μg L⁻¹ and a 95th percentile of 4.895 μg L⁻¹. For the six tetra to hepta PBDE congeners, the median was 1.8 ng g⁻¹ l.w. (95th percentile: 16.2 ng g⁻¹ l.w.). None of our study subjects had a body burden that exceeded the biomonitoring equivalents for dioxins or PBDE congener 99 or the human biomonitoring values for ndl-PCBs. Likewise the study group did not exceed German reference values or values obtained in similar investigations.Overall, our study did not exhibit elevated internal exposures. The results also hint further decreasing tendencies for PCDD/Fs, PCBs, and PBDEs in Germany and demonstrates that people in the vicinity of a reclamation plant with no indication of an environmental contamination did not exhibit elevated internal exposures.     

Relationships between adiposity and postural control in girls during balance tasks of varying difficulty

ObjectiveThis study aimed to examine associations between postural control and body composition in 8–10-year-old girls.MethodsAn observational cross-sectional study was conducted in 47 girls who were healthy-weight/overweight/obese [body mass index (BMI) percentile]. Girls participated in six postural control conditions of varying difficulty (standing with malleoli touching, tandem stance leading with dominant and non-dominant foot, repeated with eyes open and closed). Postural control outcomes included Centre of Pressure (COP) sway area, COP principal and minor axis length and COP maximum velocity. Data were analysed using linear mixed modelling.ResultsBMI percentile was positively associated with COP sway area (p = 0.034) and principal axis (p = 0.030) during tandem stance non-dominant foot leading with eyes closed and COP principal axis during tandem stance dominant foot leading with eyes open (p = 0.045). BMI percentile significantly interacted with postural control conditions of varying difficulty to predict postural control outcomes (p ≤ 0.035), notable for tandem stance positions [all four COP sway outcomes in tandem stance non-dominant foot leading eyes closed; tandem stance dominant foot leading with eyes open and closed (two COP sway outcomes each)].ConclusionsGirls with greater adiposity may have impairments in postural control, but only during more challenging postural control conditions. In contrast, BMI has little role to play in girls’ postural control in easier postural control conditions (standing with feet together). These findings may suggest potential functional or safety considerations when girls with overweight/obesity are performing demanding postural control tasks (such as during sport or physical activity).     

Longitudinal study of acculturation and BMI change among Asian American men

BackgroundCross-sectional studies examining the association between Western acculturation and BMI in Asians have been inconsistent, and studies on BMI change are lacking.ObjectiveThis study examined the associations between indicators of acculturation (generational status, length of US residence, and age at immigration) and overweight (BMI ≥ 25 kg/m²) as well as 5-year BMI changes in 7,073 Chinese, Japanese, Korean, Filipino, and Vietnamese men who lived in the US and were 44–71 years old at baseline of the California Men's Health Study (2002–2003).MethodsIndicators of acculturation were reported at baseline. Repeated clinical measures of BMI were extracted from electronic health records (2005–2012).ResultsUsing generalized estimating equations we found that lower generational status, shorter duration of US residence and older age at immigration were inversely associated with being overweight. However, analysis of BMI curves using linear mixed models showed that shorter length of US residence and older age at immigration were associated with larger 5-year increases in BMI.ConclusionsAsian immigrants who were less acculturated had larger BMI increases as they became more acculturated but had not achieved overweight status. Healthy weight interventions among Asians immigrants may be most effective when targeting weight maintenance early in the process of acculturation.     

Objectively-measured sedentary time and cardiometabolic health in adults with severe obesity

It is unknown whether sedentary behavior is independently associated with the cardiometabolic health of adults with severe obesity. Additionally, there is debate regarding how best to derive meaningful indices of sedentary time (ST) from activity monitor data. A convenience sample of adults with severe obesity (N = 927; 79% female, median age 45 y, median body mass index (BMI) 46 kg/m²) completed a research assessment at one of ten US hospitals in 2006–2009 prior to bariatric surgery. Cardiometabolic health was assessed via physical measures, fasting blood samples and medication use. Indices of ST were derived from StepWatch™ activity monitor data with minimum bout durations of 1 min, 10 min and 30 min. Cross-sectional associations were examined. Median (25th, 75th percentile) ST was 9.3 h/d (8.1, 10.5) in ≥ 1 min bouts, 6.5 h/d (5.2, 8.0) in ≥ 10 min bouts, or 3.2 h/d (2.1, 4.5) in ≥ 30 min bouts. Associations with ST were generally strongest with the ≥ 10 min bout duration. Independent of moderate-to-vigorous intensity physical activity, BMI and other potential confounders, 1 h/day ST in ≥ 10 min bouts was associated with higher odds of diabetes by 15% (95%CI: 1.05–1.26), metabolic syndrome by 12% (95%CI: 1.01–1.24) and elevated blood pressure by 14% (95%CI: 1.02–1.26), and was associated with 1.4 cm (95%CI: 0.9–1.9) larger waist circumference. Findings indicate the importance of considering ST as a distinct health risk among adults with severe obesity, and suggest a 10 min minimum duration may be preferable to 1 min or 30 min for establishing ST from activity monitor data.     

Elevated systolic blood pressure of children in the United States is associated with low serum 25-hydroxyvitamin D concentrations related to body mass index: National Health and Examination Survey 2007-2010

A negative association between serum 25-hydroxyvitamn D (25[OH]D) concentrations and blood pressure has been found in adults; whether a similar relationship exists in children remains unclear. We hypothesized that serum 25(OH)D concentrations of children would negatively correlate with blood pressure. Using a nationally representative sample of children aged 8 to 18 years from the National Health and Nutrition Examination Survey 2007-2010 (n = 2908), we compared serum 25(OH)D levels with diastolic and systolic blood pressure by vitamin D nutritional status categories. A high percentage of children were either vitamin D deficient (28.8%) or vitamin D insufficient (48.8%). Prehypertension was defined as blood pressure as ≥90th to <95th percentile and hypertension as ≥95th percentile by age, height, and sex national blood pressure percentile norms for children. Vitamin D–deficient children aged 8 to 13 years had higher systolic blood pressure (104.8 ± 0.7 mm Hg) than did vitamin D–sufficient children (102.3 ± 0.6 mmHg; P < .05). Controlling for age, sex, race/ethnicity, and income, systolic blood pressure was inversely associated with serum 25(OH)D concentrations (P < .03), but not when also controlling for body mass index (P = .63). A higher percentage of vitamin D–deficient and vitamin D–insufficient children (1.7%) vs vitamin D–sufficient children (0.6%) had prehypertension or hypertension. In conclusion, the association of low serum 25(OH)D concentrations with elevated systolic blood pressure in children is likely related to body weight and markers of adiposity.     

Associations between relationship stability,relationship quality,and weight loss outcomes among bariatric surgery patients

After weight loss surgery (WLS), psychosocial functioning, including the quality of social relationships, generally improves, but for a minority, relationships worsen. We examined how changes in relationship stability and quality from pre- to post-WLS relate to long-term weight loss outcomes. Postoperative patients (N = 361) completed surveys which queried relationship changes and weight loss. The sample was 95.9% Caucasian, 80.1% female, averaged 7.7 years post-WLS, with a mean age at surgery of 47.7 years (range 21–72); 87.3% had a Roux-en-Y gastric bypass. Four relationship status groups were created: Not in a relationship at surgery or follow-up (No-Rel, n = 66; 18.2%); Post-WLS relationship only (New-Rel, n = 23; 6%); Pre-WLS relationship only (Lost-Rel, n = 17; 5%); and Pre–Post Relationship (Maintainer, n = 255; 70.6%). Current BMI was 34.5 for No-Rel; 40.5 for New-Rel; 37.4 for Lost-Rel; 33.3 for Maintainers (p < .05 for Maintainers and No-Rel vs. New-Rel). These same group differences were significant for weight loss, which was not associated with gender, time since surgery, or age at time of surgery, but was associated with pre-WLS BMI (lower pre-WLS BMI was associated with greater %EWL). Analyses were repeated with pre-WLS BMI as a covariate; group differences remained significant [F (3, 355) = 3.09, p = .03], as did pre-WLS BMI, [F (1, 355) = 9.12, p = .003]. Among Maintainers, relationship quality was associated with weight loss outcomes: those with improved relationships post-WLS had significantly greater %EWL [F (2, 234) = 15.82, p < 0.000; p < .05 for Improved > (Stayed Same = Got Worse)]. Findings support the importance of assessing relationship stability and quality in pre-WLS candidates, as healthy and stable relationships may support improved long-term outcomes. Interventions to improve relationships pre-and post-WLS may increase both quality of life and weight loss outcomes.     

Sustained Active Transportation is associated with a favorable body mass index trajectory across the early school years: Findings from the Quebec Longitudinal Study of Child Development birth cohort

ObjectiveTo determine the extent to which active transportation (AT) to and from school is associated with changes in body mass index (BMI) from kindergarten (6-year-olds) through grade 2 (8-year-olds).MethodsThe sample included 1170 children (50.4% of baseline participants) who were part of the Quebec Longitudinal Study of Child Development (QLSCD), a birth cohort established in 1998 in Quebec, Canada. Data were collected by trained interviewers using structured interviews and measuring height and weight in the home with the person most knowledgeable about the child's health. Relative weight was operationalized as age- and sex-adjusted BMI Z-scores.ResultsGrowth curve analyses showed that using AT to and from school both when in kindergarten and in grade 1 was predictive of a lower BMI Z-score (coeff = - 0.18, SE = 0.09, p = 0.05) in grade 1. Using AT to and from school in kindergarten, grade 1, and grade 2 was predictive of a lower BMI Z-score (coeff = - 0.30, SE = 0.098, p = 0.003) in grade 2. No other covariates were predictive of relative weight across time, although having an overweight or obese mother was associated with a BMI Z-score of 0.39 (SE = 0.07, p < 0.001) across all time points.ConclusionSustained AT is associated with more healthful trajectories of BMI across the early school years.     

Adverse effects of long-term weight gain on microvascular endothelial function

BackgroundEndothelial dysfunction is the first stage of the atherosclerotic cascade, and independently associated with cardiovascular events. We evaluated the associations of longitudinal changes in weight, waist circumference, body fat percentage and lean mass index with changes in endothelial function.Methods521 community-based subjects who belonged to hypertensive sibships and had no history of myocardial infarction or stroke had their anthropometric measures and endothelial function assessed a mean of 8.5 years apart. Endothelial function was assessed with brachial artery ultrasound, yielding measures of flow-mediated dilation and reactive hyperemia. We used multivariable linear regression with generalised estimating equations to assess the associations of longitudinal changes (Δ) in anthropometric measures with Δ flow-mediated dilation and reactive hyperemia, adjusting for potential confounders.ResultsMean ± standard deviation age was 57.6 ± 8.7 years, 58% were women, and 72% were hypertensive. Most (84%) were overweight or obese at baseline. At end of follow-up, flow-mediated dilation and reactive hyperemia increased by 1.9 ± 7.6% and 51.2 ± 605.8% on average, respectively. In multivariable linear regression, changes in anthropometric measures were not associated with changes in flow-mediated dilation. However, Δ weight (β ± SE: −9.00 ± 2.35), Δ waist circumference (−6.78 ± 2.21) and Δ body fat percentage (−19.72 ± 5.62, P < 0.0001 for each) were inversely associated with Δ reactive hyperemia. Δ lean mass index was not associated with Δ reactive hyperemia.ConclusionsLong-term increases in weight, waist circumference and body fat percentage are associated with progressive worsening of microvascular endothelial function, but not conduit vessel endothelial function, in subjects without a history of cardiovascular events, independently of risk factors.     

Graphic model of birth weight and gestational age in Monastir,Tunisia

BackgroundBirth weight for gestational age curves provide to clinicians available references to assess fetal growth in individual infants and in populations. In Tunisia, until now, only North American based references were used. The objective of this study was to create national reference curves for birth weight and to compare these to those actually used in our maternities.MethodsA retrospective population based study was performed over a period of 11 years (from January 1994 to December 2004) using the register of births database of the region of Monastir. We studied a total of 75,751 births. Gestational age of infants ranged from 28 to 43 weeks. Fifth, tenth, 25th, 50th, 75th, 90th and 95th percentiles for weight were calculated by polynomial linear regression of the following general form to construct the clinical curves (Y = a + bX + cX²).ResultsThe database included 38,646 males and 37,105 females (sex ratio: 1.04). The resulting male and female curves provide smoothed percentiles cutoffs for defining small and large for gestational age births. An actual difference does exist between our curves and those routinely used.ConclusionThese constructed smoothed gestational curves can be used as a useful tool for assessing birth weight and to evaluate clinical or public health interventions to enhance fetal growth.     

Executive function mediates prospective relationships between sleep duration and sedentary behavior in children

Childhood sedentary behavior has been linked to increased obesity risk. Prior work has identified associations between sedentary behavior, executive function (EF), and sleep. This study tested the hypothesis that reduced sleep duration may adversely impact EF and lead to increased childhood sedentary behavior. Southern California schoolchildren participating in the school-based health promotion program Pathways to Health (N = 709) were assessed annually from 4th through 6th grades (2010 − 2013) on self-report measures of sedentary behavior, sleep duration, and executive function. A series of path models were specified treating average nightly sleep duration and weekend wake/bed-time shift at 4th grade as predictors of 6th grade sedentary behavior. Four EF subdomains were tested as potential mediators of longitudinal associations at 5th grade. Significant associations between average nightly sleep duration, EF and sedentary behavior were identified (p < 0.05), adjusting for participant gender, physical activity, SES, ethnicity, program group assignment, and the presence/absence of parental screen time rules. Fifth grade overall EF (p < 0.05)—and in particular the subdomains of inhibitory control (p < 0.05) and organization of materials (p < 0.01)—significantly mediated the relationship between 4th grade sleep duration and 6th grade sedentary behavior (p < 0.05). Furthermore, delay of weekend bed- or wake-times relative to weekdays was prospectively associated with decreased overall EF (p < 0.05), but not increased sedentary behavior (p = 0.35 for bed-time delay; p = 0.64 for wake-time delay), irrespective of average nightly sleep duration. Findings suggest that sleep promotion efforts may reduce children's sedentary behavior both directly and indirectly through changes in EF.     

Joint effects of age and body mass index on the incidence of hypertension subtypes in the China Health and Nutrition Survey: A cohort study over 22 years

ObjectivesWe seek to investigate the joint effects of age and body mass index (BMI) on the incident hypertension subtypes among Chinese adults during 1989–2011.MethodsWe investigated the Incidence rates (IRs, per 100 person-years) of hypertension subtypes, adjusted relative risks (RRs) and population attributable risk percent (PAR%) of BMI for hypertension, and clarified the age-specific effect of BMI on incident hypertension utilizing a dynamic cohort study from the China Health and Nutrition Survey (CHNS) 1989–2011.ResultsNormotensive participants (n = 53,028) at baseline were included, with mean age was 41.7 (95% CI, 41.6–41.7) years old. During a total of 118,694 person years (average was 6.38 years) of follow-up, a total of 5208 incident cases of hypertension were documented. The IRs of hypertension were 4.4 (95% CI, 4.3–4.5), which increased gradually by age and BMI (P_trend < 0.001). Compared with those with BMI < 22 kg/m², the RR of hypertension was 3.13 (95% CI, 2.84–3.45) in the group with BMI ≥ 28 kg/m². The PAR% (BMI > 22 vs. BMI < 22) for hypertension in Chinese population was 32% (95% CI, 29–34%). Similar trends were observed in all age and BMI groups for both isolated systolic hypertension and systolic–diastolic hypertension, which were mainly affected by age. In contrast, the peak IR of isolated diastolic hypertension was observed in participants aged 30–49 years with higher BMIs.ConclusionsThe PAR% (IR of BP ≥ 140/90 or treatment for BMI > 22 vs. IR for BMI < 22) of elevated body weight for hypertension was 32% in Chinese population.     

Vitamin D,bone mineral density and body mass index in eating disorder patients

AimTo investigate associations of vitamin D with BMD and BMI in ED patients.MethodsVitamin D, BMD and BMI for 50 patients admitted to a specialised ED inpatient unit were measured. Patients were aged 15–54 years with BMI 8–25 kg/m².ResultsOf the patients, 18% were vitamin D deficient. There was a significant linear relationship between vitamin D and BMD T-score at the lumbar spine (p = 0.029), femoral neck (p < 0.001) and total hip (p = 0.001). There was no relationship between vitamin D and BMI. There was a significant linear relationship between BMI and BMD T-score at the lumbar spine (p < 0.001), femoral neck (p = 0.008) and total hip (p = 0.001).ConclusionsLow vitamin D and low BMI are associated with low BMD in ED patients. Despite widespread belief that it is not necessary, our findings suggest it is appropriate to measure vitamin D in ED patients. It should not be assumed ED patients take supplements.     

Body weight dissatisfaction: A comparison of women with and without eating disorders

ObjectiveBody dissatisfaction is present in a majority of women without eating disorders (EDs), and almost all women with EDs. We compared body dissatisfaction in women with and without EDs to determine at which BMI women are content with their weight, and to determine if body dissatisfaction is affected by the presence of purging behaviours.MethodsWe assessed women, age 18 to 55 with an ED (N = 431) and without an ED (N = 719) using the discrepancy between their current and desired BMI. This measure of body weight dissatisfaction (BWD) has been validated as being representative of overall body dissatisfaction. We also measured perceptions of (i) Body Appearance and (ii) Body Image to confirm our results.ResultsWomen with and without EDs wished to lose weight until very low weights were achieved (BMI 15–16 kg/m² and BMI 18–19 kg/m² respectively). BWD is higher in women with EDs (median 1.77, IQR 0–4.61) than women without EDs (median 0.85, IQR 0–1.80, p < 0.001). Purging behaviours in women with EDs were associated with lower BMIs to achieve body satisfaction (BMI 15–16 kg/m²) than women who did not purge (16–17 kg/m²).ConclusionsBody weight dissatisfaction is highly prevalent amongst women with and without EDs. Understanding body weight dissatisfaction in women with EDs and its association with purging may assist in the prevention, detection and treatment of these disorders. Women with EDs should be informed that body weight dissatisfaction will not resolve with the cessation of their disorder, as it is prevalent within the general population.     

Dog walking among adolescents: Correlates and contribution to physical activity

PurposeTo assess the association of dog walking with adolescents' moderate-to-vigorous physical activity (MVPA) and body mass index (BMI), and identify correlates of dog walking.Methods/designParticipants were 12–17 year-olds (n = 925) from the Baltimore, MD and Seattle, WA regions. Differences in accelerometer-assessed minutes/day of MVPA and self-reported BMI (percentile) were compared among adolescents (1) without a dog (n = 441) and those with a dog who (2) did (≥ 1 days/week, n = 300) or (3) did not (n = 184) walk it. Correlates of (1) dog walking (any vs. none) among adolescents with dogs (n = 484), and (2) days/week of dog walking among dog walkers (n = 300) were investigated. Potential correlates included: demographic, psychosocial, home environment, perceived neighborhood environment, and objective neighborhood environment factors.Results52% of adolescents lived in a household with a dog, and 62% of those reported dog walking ≥ 1 day/week. Dog walkers had 4–5 more minutes/day of MVPA than non-dog-walkers and non-dog-owners. BMI was not associated with dog walking or ownership. Among households with dogs, adolescents who lived in objectively walkable neighborhoods were 12% more likely to walk their dog than those in less walkable neighborhoods. Among dog walkers, having a multi-family home, college-educated parent, lower perceived traffic safety, higher street connectivity and less mixed use were related to more days/week of dog walking.ConclusionsDog walkers had 7–8% more minutes/day of MVPA than non-dog walkers, and correlates of dog walking were found at multiple levels of influence. Results suggest multilevel interventions that include both environmental and psychosocial components to increase dog walking should be evaluated.