Prevalence of vitamin D insufficiency and risk factors for type 2 diabetes and cardiovascular disease among African migrant and refugee adults in Melbourne

Migration to industrialised countries poses a “double whammy” for type 2 diabetes among sub-Saharan African migrant and refugee adults. This population group has been found to be at an increased risk of obesity and type 2 diabetes, which may be further aggravated by inadequate vitamin D status. Thus, this study aimed to describe the demographics of vitamin D insufficiency, obesity, and risk factors for type 2 diabetes among sub-Saharan African migrants and refugees aged 20 years or older living in Melbourne, Australia (n=49). Data were obtained by a questionnaire, medical assessment, and fasting blood samples. The mean serum 25-hydroxyvitamin D level was 27.3 nmol/L (95% CI: 22.2, 32.4 nmol/L); with 25-hydroxyvitamin D levels <50 nmol/L occurring in 88% of participants. Participants displayed a cluster of risk factors for type 2 diabetes and cardiovascular disease: 62% were overweight or obese, 47% had insulin resistance (HOMA-IR ≥2), 25% had low density lipoprotein cholesterol levels ≥3.5 mmol/L, 24.5% had high density lipoprotein cholesterol levels ≤1.03 mmol/L, 34.6% had borderline or high levels of total cholesterol (≥5.2 mmol/L), 18.2% had borderline or high levels of triglyceride (≥1.7 mmol/L), and 16% had hypertension (systolic blood pressure ≥140 mmHg or diastolic blood pressure ≥90 mmHg). These findings suggest that sub-Saharan African migrants and refugees may be at risk of type 2 diabetes and atherosclerosis-related diseases such as ischemic heart disease, stroke, and peripheral vascular disease. Well-designed vitamin D interventions that incorporate lifestyle changes are urgently needed in this sub-population.

Socio-demographic characteristics of children experiencing socioeconomic disadvantage who meet physical activity and screen-time recommendations : the READI study

Objective - To identify socio-demographic characteristics of children from socioeconomically disadvantaged neighbourhoods who meet physical activity and screen recommendations.
Method - Children aged 5–12 years (n = 373; 45% boys) were recruited in 2007 from socioeconomically disadvantaged urban and rural areas of Victoria, Australia. Children's physical activity, height and weight were objectively measured. Mothers reported their highest level of education, and proxy-reported their child's usual screen-time. Odds ratios (OR) and 95% confidence intervals (95% CI) examined odds of meeting physical activity (> 60 minutes/day) and screen (≤ 120 minutes/day) recommendations according to socio-demographic characteristics.
Results - Approximately 84% of children met physical activity and 43% met screen recommendations. Age was inversely associated with odds of meeting physical activity and screen recommendations, and overweight/obese status was associated with lower odds of meeting screen recommendations (boys: OR = 0.39, 95%CI = 0.16–0.95; girls: OR = 0.47, 95%CI = 0.26–0.83). Among boys, living in a rural area was positively associated with meeting screen recommendations (OR = 3.08, 95%CI = 1.42–6.64). Among girls, high levels of maternal education were positively associated with meeting screen recommendations (OR = 2.76, 95%CI = 1.33–5.75).
Conclusion - Specific socio-demographic characteristics were associated with odds of meeting physical activity and screen recommendations. Identifying factors associated with such ‘resilience’ among this group may provide important learnings to inform future physical activity promotion initiatives.

Interventions to promote cycling: a systematic review

Objectives To determine what interventions are effective in promoting cycling, the size of the effects of interventions, and evidence of any associated benefits on overall physical activity or anthropometric measures.

Design Systematic review.

Data sources Published and unpublished reports in any language identified by searching 13 electronic databases, websites, reference lists, and existing systematic reviews, and papers identified by experts in the field.

Review methods Controlled “before and after” experimental or observational studies of the effect of any type of intervention on cycling behaviour measured at either individual or population level.

Results Twenty five studies (of which two were randomised controlled trials) from seven countries were included. Six studies examined interventions aimed specifically at promoting cycling, of which four (an intensive individual intervention in obese women, high quality improvements to a cycle route network, and two multifaceted cycle promotion initiatives at town or city level) were found to be associated with increases in cycling. Those studies that evaluated interventions at population level reported net increases of up to 3.4 percentage points in the population prevalence of cycling or the proportion of trips made by bicycle. Sixteen studies assessing individualised marketing of “environmentally friendly” modes of transport to interested households reported modest but consistent net effects equating to an average of eight additional cycling trips per person per year in the local population. Other interventions that targeted travel behaviour in general were not associated with a clear increase in cycling. Only two studies assessed effects of interventions on physical activity; one reported a positive shift in the population distribution of overall physical activity during the intervention.

Conclusions Community-wide promotional activities and improving infrastructure for cycling have the potential to increase cycling by modest amounts, but further controlled evaluative studies incorporating more precise measures are required, particularly in areas without an established cycling culture. Studies of individualised marketing report consistent positive effects of interventions on cycling behaviour, but these findings should be confirmed using more robust study designs. Future research should also examine how best to promote cycling in children and adolescents and through workplaces. Whether interventions to promote cycling result in an increase in overall physical activity or changes in anthropometric measures is unclear.

Involvement of young Australian adults in meal preparation : cross-sectional associations with abdominal obesity and body mass index

Previous research has shown that involvement in meal preparation is positively associated with better diet quality. However, it is unclear whether there is an association between involvement in meal preparation and being overweight or obese. This study investigated whether the level of involvement in meal preparation was associated with objectively measured weight status in young adults. During 2004-2006, a national sample of 1,996 Australian adults aged 26 to 36 years completed a self-administered questionnaire including questions on sociodemographic characteristics, diet, and physical activity. Participants were asked to report who usually prepared the main meal on working days and responses were categorized as “myself,” “shared,” or “someone else.” Waist circumference, weight, and height were measured by trained staff. Moderate abdominal obesity was defined as waist circumference >94 cm for men and >80 cm for women. Overweight was defined as body mass index (calculated as kg/m2) >25. Prevalence ratios were calculated using log binomial regression. After adjusting for age, education, and leisure time physical activity, men who shared the meal preparation had a slightly lower prevalence of moderate abdominal obesity (prevalence ratio=0.92; 95% confidence interval [CI]: 0.86 to 0.99) than those whose meals were usually prepared by someone else. There was no association with having sole responsibility (prevalence ratio=0.99; 95% CI: 0.92 to 1.06). There were no associations between level of involvement in meal preparation and being overweight (shared responsibility prevalence ratio=0.99; 95% CI: 0.92 to 1.07; sole responsibility prevalence ratio=0.98; 95% CI: 0.91 to 1.05). For women, level of involvement was not associated with moderate abdominal obesity (shared responsibility prevalence ratio=0.93; 95% CI: 0.84 to 1.03; sole responsibility prevalence ratio=0.94; 95% CI: 0.86 to 1.03) or being overweight (shared responsibility prevalence ratio=0.93; 95% CI: 0.84 to 1.02; sole responsibility prevalence ratio=0.93; 95% CI: 0.85 to 1.02). In this sample of young adults, level of involvement in meal preparation was not strongly related to weight status.

Prevalence of obesity and the relationship between the body mass index and body fat : cross-sectional, population-based data

Background: Anthropometric measures such as the body mass index (BMI) and waist circumference are widely used as convenient indices of adiposity, yet there are limitations in their estimates of body fat. We aimed to determine the prevalence of obesity using criteria based on the BMI and waist circumference, and to examine the relationship between the BMI and body fat.

Methodology/Principal Findings: This population-based, cross-sectional study was conducted as part of the Geelong Osteoporosis Study. A random sample of 1,467 men and 1,076 women aged 20–96 years was assessed 2001–2008. Overweight and obesity were identified according to BMI (overweight 25.0–29.9 kg/m2; obesity $30.0 kg/m2) and waist circumference (overweight men 94.0–101.9 cm; women 80.0–87.9 cm; obesity men $102.0 cm, women $88.0 cm); body fat mass was assessed using dual energy X-ray absorptiometry; height and weight were measured and lifestyle factors documented by self-report. According to the BMI, 45.1% (95%CI 42.4–47.9) of men and 30.2% (95%CI 27.4–33.0) of women were overweight and a further 20.2% (95%CI 18.0–22.4) of men and 28.6% (95%CI 25.8–31.3) of women were obese. Using waist circumference, 27.5% (95%CI 25.1–30.0) of men and 23.3% (95%CI 20.8–25.9) of women were overweight, and 29.3% (95%CI 26.9–31.7) of men and 44.1% (95%CI 41.2–47.1) of women, obese. Both criteria indicate that approximately 60% of the population exceeded recommended thresholds for healthy body habitus. There was no consistent pattern apparent between BMI and energy intake. Compared with women, BMI overestimated adiposity in men, whose excess weight was largely attributable to muscular body builds and greater bone mass. BMI also underestimated adiposity in the elderly. Regression models including gender, age and BMI explained 0.825 of the variance in percent body fat.

Conclusions/Significance: As the BMI does not account for differences in body composition, we suggest that gender- and age-specific thresholds should be considered when the BMI is used to indicate adiposity.

Accounting for the multidimensional nature of the relationship between adult obesity and socio-economic status : the French second National Individual Survey on Food Consumption (INCA 2) dietary survey (2006–07)

The objective was to study the multidimensional nature of the relationship between adult obesity (OB) and socio-economic status (SES),
using comprehensive indices of SES taken separately or synthesised in an overall index. A nationally representative sample of adults aged
18–79 years was taken from the French second National Individual Survey on Food Consumption (INCA 2) dietary survey (2006–07).
Weight and height were measured and OB defined as BMI $ 30 kg/m². SES variables were reported in questionnaires and included
occupation, education and characteristics of household wealth. Composite indices of SES (household wealth and overall SES indices)
were computed by correspondence analysis, and relationships with OB were investigated with logistic regression analysis. In total, 11·8
(95% CI 10·1, 13·4) % of French adults were obese, without significant difference by sex. While no significant relationship was observed
in men, all SES indicators were inversely correlated to OB in women. Both education and the household wealth index were retained in the
stepwise multivariate model, confirming that different socio-economic variables are not necessarily proxies of each other regarding the OB
issue. On the other hand, ‘controlling for SES’ while including several measures of SES in multivariate models may lead to collinearity, and
thus over-adjustment. A more integrative approach may be to derive a synthetic index by including the SES factors available in a given
study. Beyond this methodological perspective, understanding how OB is related to the different dimensions of SES should help to
target the more vulnerable groups and increase the effectiveness of prevention.

Changes in body mass index and health related quality of life from childhood to adolescence

Objective . To determine longitudinal relationships between body mass index (BMI) and health-related quality of life (HRQoL) in an adolescent population sample.
Design. Data collected in 2000 and 2005 within the Health of Young Victorians longitudinal cohort study.
Setting. Originally a community sample of elementary school students in Victoria, Australia. Follow-up occurred in either secondary schools or individuals homes.
Participants. Cohort recruited in 1997 via a random sampling design from Victorian elementary schools. Originally comprising 1 943 children, 1 569 (80.8%) participated in 2000 (wave 2, 8 – 13 years) and 851 (54%) in 2005 (wave 3, 13 – 19 years).
Main outcome measures. In both waves participants and their parents completed the PedsQL, a 23-item child HRQoL measure, and BMI z-scores and status (non-overweight, overweight or obese) were calculated from measured height and weight. Associations were tested cross-sectionally and longitudinally (linear regression, adjusted for baseline values)
Results. A total of 81.6% remained in the same BMI category, while 11.4% and 7.0% moved to higher and lower categories, respectively. Cross-sectional inverse associations between lower PedsQL and higher BMI categories were similar to those for elementary school children. Wave 2 BMI strongly predicted wave 3 BMI and wave 2 PedsQL strongly predicted wave 3 PedsQL. Only parent-reported Total PedsQL score predicted higher subsequent BMI, though this effect was small. Wave 2 BMI did not predict wave 3 PedsQL.
Conclusions. This novel study confi rmed previous cross-sectional associations, but did not provide convincing evidence that
BMI is causally associated with falling HRQoL or vice versa across the transition from childhood to adolescence.

Prevalence of vitamin D deficiency and its determinants in Australian adults aged 25 years and older : a national, population-based study

Objective  Vitamin D deficiency is recognized as a global public health problem, but the population-based prevalence of deficiency and its determinants in Australian adults is not known. This study evaluated the vitamin D status of Australian adults aged ≥25 years and risk factors associated with vitamin D deficiency in this population.

Design and Patients  We studied a national sample of 11 247 Australian adults enrolled in the 1999/2000 Australian Diabetes, Obesity and Lifestyle (AusDiab) study drawn from 42 randomly selected districts throughout Australia.

Measurements  Serum concentrations of 25-hydroxyvitamin D [25(OH)D] were measured by immunoassay. Vitamin D deficiency was defined as a concentration <50 nmol/l. Information on demographic and lifestyle factors was derived from interview-administered questionnaires.

Results  The mean serum 25(OH)D concentration was 63 nmol/l (95% CI: 59–67 nmol/l). Only 4% of the population had a level <25 nmol/l, but the prevalence of vitamin D deficiency (<50 nmol/l) was 31% (22% men; 39% women); 73% had levels <75 nmol/l. The prevalence of vitamin D deficiency increased significantly with age, was greater in women, in those of non-Europid origin, in the obese and those who were physically inactive and with a higher level of education. Deficiency was also more common during winter and in people residing in southern Australia (latitude >35°S); 42% of women and 27% of men were deficient during summer–autumn, which increased to 58% and 35%, respectively, during winter–spring.

Conclusion  Vitamin D deficiency is common in Australia affecting nearly one-third of adults aged ≥25 years. This indicates that strategies are needed at the population level to improve vitamin D status of Australians.

Weight status associations with physical activity intensity and physical self-perceptions in 10-to 11-year-old children

The study examined associations between children’s weight status, physical activity intensity, and physical self-perceptions. Data were obtained from 409 children (224 girls) aged 10–11 years categorized as normal-weight or overweight/obese. Physical activity was assessed using accelerometry, and children completed the Physical Self-Perception Profile. After controlling for the effects of age, maturation, and socioeconomic status vigorous physical activity was significantly associated with normal-weight status among boys (OR = 1.13, p = .01) and girls (OR = 1.13, p = .03). Normal-weight status was significantly associated with perceived Physical Condition (Boys: OR = 5.05, p = .008; Girls: OR = 2.50, p = .08), and Body Attractiveness (Boys: OR = 4.44, p = .007; Girls: OR = 2.56, p = .02). Weight status of 10–11 year old children was significantly associated with time spent in vigorous physical activity and self-perceptions of Body Attractiveness and Physical Condition.