‘MILK VOLUME, MILK FAT AND CHILDHOOD FRACTURE RISK

BACKGROUND

Children who do not consume cow’s milk have been associated with an increased risk of fracture. Cow’s milk is consumed by most North American children yet the relationships between the volume of cow’s milk consumed, the fat content of cow’s milk and childhood fracture risk are unclear.

OBJECTIVES

The primary objective was to evaluate whether volume of cow’s milk consumed between ages 1 - 3 was associated with fracture between ages 3 - 10. Secondary objectives explored whether milk-fat consumed between ages 1 - 3 was associated with fracture between ages 3 - 10 and whether milk-fat content modified the relationship between milk volume and fracture.

DESIGN/METHODS

This was a prospective analysis of 2466 healthy urban children with exposure between 1 and 3 years of age and outcome between 3 and 10 years of age enrolled in the TARGet Kids! -Applied Research Group for Kids cohort. The primary exposure was the volume of cow’s milk consumed and the secondary exposure was the average percentage of milk-fat consumed by each child. The outcome was one or more fractures experienced, measured as yes or no. A modified Poisson regression was used to evaluate the relationship between volume of cow’s milk at exposure, and one or more fractures at outcome. The same analysis was used to explore the relationship between cow’s milk-fat and fracture. Effect modification by milk-fat consumed on the relationship between milk volume and fracture risk was explored by adding an interaction term to the statistical model.

RESULTS

In the primary adjusted analysis, a statistically significant association between the volume of cow’s milk consumed at exposure and risk of one or more fractures at outcome was not observed (aRR= 1.04; 95% CI: 0.87 to 1.26). In the secondary analysis, a statistically significant association between cow’s milk-fat consumed at exposure and fracture risk at outcome was also not observed (aRR= 1.05; 95% CI: 0.84 to 1.31). Cow’s milk-fat did not modify the relationship between milk volume and risk of fracture. (p= 0.24).

CONCLUSION

In this prospective cohort study of young children, we did not identify a protective effect of early childhood volume of cow’s milk or milk-fat consumption on fracture risk in later childhood. Future research in young children is needed to evaluate specific low impact fracture mechanisms, which may be more sensitive to nutritional factors.

ACCELERATED GROWTH IN EARLY CHILDHOOD IS ASSOCIATED WITH INCREASED SYSTOLIC AND DIASTOLIC BLOOD PRESSURE

BACKGROUND

Maternal obesity, low birthweight, and accelerated growth have been shown to be associated with elevated blood pressure in children. However, it is unknown which growth periods are associated with blood pressure, and whether birthweight or maternal obesity modify the relationship between growth and blood pressure in early childhood.

OBJECTIVES

We examined the relationship between age- and sex-standardized body mass index (zBMI) growth trajectories with longitudinal measures of systolic (SBP) and diastolic (DBP) blood pressure in early childhood.

DESIGN/METHODS

We collected repeated measures of zBMI and blood pressure in 2502 children participating in the TARGet Kids! cohort. In stage 1 we used linear spline multilevel models to estimate each child’s zBMI at birth and zBMI growth trajectories in early infancy (0–3 m), late infancy (3–18 m) and toddler years (18–36 m). In stage 2 we used generalized estimating equations to examine the relationship between zBMI at birth and zBMI growth with repeated measures of SBP and DBP from 3 to 6 years of age. We tested for effect modification by birthweight and maternal obesity status by inclusion of interaction terms in each growth period.

RESULTS

After adjusting for confounders and prior growth, a 1 standard deviation unit increase in zBMI growth per month in early infancy (β=0.59; 95% CI 0.32,0.87) and late infancy (β=0.73; 95% CI 0.44,1.01), were associated with higher SBP. Growth in the toddler years was not significantly associated with SBP (p=0.08). Similar but smaller associations were observed for zBMI growth and DBP in early (β=0.29; 95% CI 0.04, 0.53) and late infancy (β=0.42; 95% CI 0.18, 0.66). Birthweight status modified (p=0.004) the relationship between zBMI growth and SBP during late infancy, with the strongest positive association observed in the low birthweight group. During toddler years, birthweight status modified the relationship between zBMI growth with SBP (p=0.03) and DBP (p=0.04), with the strongest positive association observed in the low birthweight group, followed by the high birthweight group. Maternal obesity status modified (p= 0.03) the relationship between zBMI growth with DBP in late infancy, with a stronger association observed among children of mothers with obesity.

CONCLUSION

Accelerated growth in early and late infancy are associated with increased blood pressure in early childhood. Growth during late infancy and toddler years may impact blood pressure differently in children born with high and low birthweights and high maternal BMI, suggesting prospective windows and risk groups to target interventions.

EVALUATING THE PREDICTIVE VALIDITY OF THE NIPISSING DISTRICT DEVELOPMENTAL SCREEN IN PRIMARY CARE SETTINGS AT THE 18-MONTH HEALTH SUPERVISION VISIT

BACKGROUND

The Canadian Paediatric Society (CPS) recommends that every Canadian physician caring for young children provide an enhanced 18-month well-baby visit including the use of a developmental screening tool, such as the Nipissing District Developmental Screen (NDDS). The Province of Ontario implemented an enhanced 18-month well-baby visit specifically emphasizing the NDDS, which is now widely used in Ontario primary care. However, the diagnostic accuracy of the NDDS in identifying early developmental delays in real-world clinical settings is unknown.

OBJECTIVES

To assess the predictive validity of the NDDS in primary care for identifying developmental delay and prompting a specialist referral at the 18-month health supervision visit.

DESIGN/METHODS

This was a prospective longitudinal cohort study enrolling healthy children from primary care practices. Parents completed the 18-month NDDS during their child’s scheduled health supervision visit between January 2012 and February 2015. Using a standardized data collection form, research personnel abstracted data from the child’s health records regarding the child’s developmental outcomes following the 18-month assessment. Data collected included confirmed diagnoses of a development delay, specialist referrals, family history, and interventions. Research personnel were blind to the results of the NDDS. We assessed the diagnostic test properties of the NDDS with a confirmed diagnosis of developmental delay as the criterion measure. The specificity, sensitivity, positive predictive value, and negative predictive value were calculated, with 95% confidence intervals.

RESULTS

We included 255 children with a mean age of 18.5 months (range, 17.5–20.6) and 139 (55%) were male. 102 (40%) screened positive (1+ flag result on their NDDS). A total of 48 (19%) children were referred, and 23 (9%) had a confirmed diagnosis of a developmental delay (speech and language: 14; gross motor: 4; autism spectrum disorder: 3; global developmental delay: 1; developmental delay: 1). The sensitivity was 74% (95% CI: 52–90%), specificity was 63% (95% CI: 57–70%), positive predictive value was 17% (95% CI:10–25%), and the negative predictive value was 96% (95% CI: 92–99%).

CONCLUSION

For developmental screening tools, sensitivity between 70%-80% and specificity of 80% have been suggested. The NDDS has moderate sensitivity and specificity in identifying developmental delay at the 18-month health supervision visit. The 1+NDDS flag cut-point may lead to overdiagnosis with more children with typical development being referred, leading to longer wait times for specialist referrals among children in need. Future work includes investigating the diagnostic accuracy of combining the NDDS with other screening tools.

DOES BREASTFEEDING DURATION INFLUENCE FAMILY FOOD INSECURITY?

BACKGROUND

Across all demographics, families without consistent access to adequate food place children at health risk. Consequences may persist beyond early life into adulthood. Public policy positions breastfeeding, the ideal nutrition for infants, as an important solution to reducing family food insecurity (FFI). However, few studies have investigated the association between breastfeeding duration and FFI.

OBJECTIVES

To evaluate the association between total breastfeeding duration and FFI in Canadian urban children.

DESIGN/METHODS

A cross-sectional study was conducted of children aged 0–2 years, from a practice-based child research network. Total breastfeeding duration was collected from parent-reported questionnaires. FFI was measured using 2-item food insecurity and validated 1-item NutriSTEP screens. Multivariable regression analysis was performed adjusting for pre-specified covariates.

RESULTS

Among 3838 children, the mean total breastfeeding duration was 10.6 months (SD=6.7). Families with food insecurity (14.7%) had increased odds of younger mothers, more males and older and more children. In adjusted model, breastfeeding duration was not associated with FFI (OR 0.99; 95% CI 0.98, 1.01). Low-income families were 9 times more likely to be family food insecure than high-income families (p=0.00).

CONCLUSION

Contrary to public policy, our study found no association between breastfeeding and family food insecurity (FFI). However, other factors may predominate, in particular family income and structure. Given the detrimental impact of FFI, further research is needed to understand the role of infant feeding practices within the larger political, policy and cultural framework.

Human S-cone electroretinograms obtained by silent substitution stimulation

We used triple silent substitution stimuli to characterize human S-cone electroretinograms (ERGs) in normal trichromats. Short-wavelength-cone (S-cone) ERGs were found to have different morphological features and temporal frequency response characteristics compared to ERGs derived from L-cones, M-cones, and rod photoreceptors in normal participants. Furthermore, in two cases of retinal pathology, blue cone monochromatism (BCM) and enhanced S-cone syndrome (ESCS), S-cone ERGs elicited by our stimuli were preserved and enhanced, respectively. The results from both normal and pathological retinae demonstrate that triple silent substitution stimuli can be used to generate ERGs that provide an assay of human S-cone function.

The impact of daycare attendance on outdoor free play in young children

Background

Outdoor free play is important for healthy growth and development in early childhood. Recent studies suggest that the majority of time spent in daycare is sedentary. The objective of this study was to determine whether there was an association between daycare attendance and parent-reported outdoor free play.

Methods

Healthy children aged 1-5 years recruited to The Applied Research Group for Kids! (TARGet Kids!), a primary care research network, were included. Parents reported daycare use, outdoor free play and potential confounding variables. Multivariable linear regression was used to determine the association between daycare attendance and outdoor free play, adjusted for age, sex, maternal ethnicity, maternal education, neighborhood income and season.

Results

There were 2810 children included in this study. Children aged 1 to <3 years (n = 1388) and ≥3 to 5 years (n = 1284) who attended daycare had 14.70 min less (95% CI -20.52, -8.87; P < 0.01) and 9.44 min less (95% CI -13.67, -5.20; P < 0.01) per day of outdoor free play compared with children who did not attend daycare, respectively.

Conclusions

Children who spend more time in daycare have less parent-reported outdoor free play. Parents may be relying on daycare to provide opportunity for outdoor free play and interventions to promote increased active play opportunities outside of daycare are needed.

CNGB3 mutations cause severe rod dysfunction

PURPOSE

Congenital achromatopsia or rod monochromatism is a rare autosomal recessive condition defined by a severe loss of cone photoreceptor function in which rods purportedly retain normal or near-to-normal function. This report describes the results of electroretinography in two siblings with CNGB3-associated achromatopsia.

METHODS

Full field light- and dark-adapted electroretinograms (ERGs) were recorded using standard protocols detailed by the International Society for Clinical Electrophysiology of Vision (ISCEV). We also examined rod-mediated ERGs using series of stimuli that varied over a 6 log unit range of retinal illuminances (-1.9-3.5 log scotopic trolands).

RESULTS

Dark-adapted ERGs in achromatopsia patients exhibited severely reduced b-wave amplitudes with abnormal b:a ratios (1.3 and 0.6). In comparison, the reduction in a-wave amplitude was less marked. The rod-mediated ERG took on an electronegative appearance at high-stimulus illuminances.

CONCLUSION

Although the defect that causes achromatopsia is primarily in the cone photoreceptors, our results reveal an accompanying disruption of rod function that is more severe than has previously been reported. The differential effects on the b-wave relative to the a-wave points to an inner-retinal locus for the disruption of rod function in these patients.

Three year Experience of Non-Melanoma Skin Cancer in a General Practice

We report 85 lesions of non-melanoma skin cancer in 58 patients, representing 9% of the minor surgical workload of a single general practitioner. Cases were studied in order to describe pathology, management and outcomes. Eighteen percent of lesions were referred, mainly because of central facial site and larger size. Of the lesions treated in the surgery, all but four were treated surgically. Quantitative margins of lateral and deep excision were reported for 50% and 30% of specimens respectively. Lateral histological margins of clearance were narrower for head and neck lesions. Incomplete excision occurred in 4%. There was one recurrent lesion after two years of follow-up. A majority of non-melanoma skin cancers at this clinic were managed safely without referral to secondary care. Quantitative reporting of tumour free margins for skin cancer is lacking.

The morphology of human rod ERGs obtained by silent substitution stimulation

Purpose

To record transient ERGs from the light-adapted human retina using silent substitution stimuli which selectively reflect the activity of rod photoreceptors. We aim to describe the morphology of these waveforms and examine how they are affected by the use of less selective stimuli and by retinal pathology.

Methods

Rod-isolating stimuli with square-wave temporal profiles (250/250 ms onset/offset) were presented using a 4 primary LED ganzfeld stimulator. Experiment 1: ERGs were recorded using a rod-isolating stimulus (63 ph Td, rod contrast, C_rod = 0.25) from a group (n = 20) of normal trichromatic observers. Experiment 2: Rod ERGs were recorded from a group (n = 5) using a rod-isolating stimulus (C_rod = 0.25) which varied in retinal illuminance from 40 to 10,000 ph Td. Experiment 3: ERGs were elicited using 2 kinds of non-isolating stimuli; (1) broadband and (2) rod-isolating stimuli which contained varying degrees of L- and M-cone excitation. Experiment 4: Rod ERGs were recorded from two patient groups with rod monochromacy (n = 3) and CSNB (type 1; n = 2).

Results

The rod-isolated ERGs elicited from normal subjects had a waveform with a positive onset component followed by a negative offset. Response amplitude was maximal at retinal illuminances <100 ph Td and was virtually abolished at 400 ph Td. The use of non-selective stimuli altered the ERG waveform eliciting more photopic-like ERG responses. Rod ERGs recorded from rod monochromats had similar features to those recorded from normal trichromats, in contrast to those recorded from participants with CSNB which had an electronegative appearance.

Conclusions

Our results demonstrate that ERGs elicited by silent substitution stimuli can selectively reflect the operation of rod photoreceptors in the normal, light-adapted human retina.

Diagnostic accuracy of developmental screening in primary care at the 18-month health supervision visit: a cross-sectional study

BACKGROUND

Communication delays are often the first presenting problem in infants with a range of developmental disabilities. Our objective was to assess the validity of the 18-month Nipissing District Developmental Screen compared with the Infant Toddler Checklist, a validated tool for detecting expressive language and other communication delays.

METHODS

A cross-sectional design was used. Children aged 18-20 months were recruited during scheduled health supervision visits. Parents completed both the 18-month Nipissing District Developmental Screen and the Infant Toddler Checklist. We assessed criterion validity (diagnostic test properties, overall agreement) for 1 or more "no" responses (1+NDDS flag) and 2 or more "no" responses (2+NDDS flag) using the Infant Toddler Checklist as a criterion measure.

RESULTS

The study included 348 children (mean age 18.6 ± 0.7 mo). The 1+NDDS flag had good sensitivity (94%, 95% confidence interval [CI] 70%-100%, and 86%, 95% CI 64%-96%), poor specificity (63%, 95% CI 58%-68%, and 63%, 95% CI 58%-69%), and fair agreement (0.26) to identify expressive speech and other communication delays, respectively. The 2+NDDS flag had low to fair sensitivity (50%, 95% CI 26%-74%, and 73%, 95% CI 50%-88%), good specificity (86%, 95% CI 82%-90%, and 88%, 95% CI 84%-92%) and moderate agreement (0.45) to identify expressive speech and other communication delays, respectively.

INTERPRETATION

The low specificity of the 1+NDDS flag may lead to overdiagnosis, and the low sensitivity of the 2+NDDS flag may lead to underdiagnosis, suggesting that infants who could benefit from early intervention may not be identified. The Nipissing District Developmental Screen does not have adequate characteristics to accurately identify children with a range of communication delays.

The Generalizability of the Paediatric Developmental Passport: A Multi-Site Randomized Controlled Trial

BACKGROUND: The Pediatric Developmental Passport (passport) is an innovative tracking tool for families of children with autism spectrum disorder (ASD). It provides a mechanism for clearly communicating appropriate regional developmental services, an opportunity track progress in accessing these developmental services and a valuable summary of the developmental care received by that child for pediatrician. A qualitative study with parents and health professionals (developmental pediatricians, developmental nurses, pediatricians) lead to the design and iterative review of the passport.

OBJECTIVES: The objective of this study was to determine the general-izability and effectiveness of the passport compared to placebo in a multi-site pragmatic randomized control trial.

DESIGN/METHODS: A pragmatic multi-site randomized controlled trial was conducted with families of children between 0-6 years of age diagnosed with ASD. Families from two different models of developmental care were enrolled into the study. One site was a sub-urban developmental consultation clinic and the second site was a shared-care model between developmental pediatricians and general pediatricians in an urban resource restricted area. All families included in the study were randomized to receive the passport or placebo (blank card). Agencies providing Autism specific behaviour therapy (ABA) within each site were contacted directly to obtain accurate contact and access status of recommended developmental services. To determine passport effectivenes a pearson’s chi square test was conducted using a significant p value of &lt;0.05.

RESULTS: Forty children with ASD were included and followed in this study. The passport proved to be significantly more effective in aiding families to contact developmental services than the placebo (blank card). A significantly larger portion of families (90.5%) with the passport contacted agencies for ABA (applied behaviour analysis) therapy compared to families with the placebo (61.9%, (p value significant at &lt;0.05). More families with the passport tended to contact ABA in less than 2 months (48%) than the placebo group (35%), but this was not statistically significant.

CONCLUSION: The pediatric developmental passport enables families of children newly diagnosed with Autism to contact necessary behavioural services more often than those who did not receive the passport after diagnosis.

The Relationship between Milk Fat Content, Vitamin D and Adiposity in Early Childhood

BACKGROUND: Fortified cow’s milk is the main dietary source of vitamin D and an important source of dietary fat for North American children. Current guidelines recommend reduced milk fat consumption to reduce childhood obesity, yet the relationship between lower milk fat, vitamin D stores and adiposity is unclear.

OBJECTIVES: The objective of this study was to determine the association between percent fat content of milk and both zBMI and 25-hydroxyvi-tamin D; secondly, to explore if volume of milk consumed modified this relationship.

DESIGN/METHODS: A cross-sectional study of healthy urban children 12-72 months of age was conducted. Bivariate multiple linear regression was used to test the association between percent milk fat content and child 25-hydroxyvitamin D and zBMI concurrently. The interaction between volume of milk consumed and percent milk fat content was examined to explore how milk volume might modify these relationships.

RESULTS: 2745 children were included in the analysis. Percent fat content of milk was positively associated with 25-hydroxyvitamin D (p=0.006), and negatively associated with zBMI (p&lt;0.0001). Children who drank homogenized milk (3.25% fat) had 6.6 nmol/L (95% CI 5.49 to 7.71) higher median 25(OH)D concentration and 0.72 lower (95% CI 0.68 to 0.76) zBMI score than children who drank skim milk (0.1% fat). Volume of milk consumed potentiated the effect of percent fat content of milk on 25-hydroxyvitamin D (p=0.003) but not on zBMI (p=0.77). Children who drank 1 cup of homogenized milk each day had a similar 25-hydroxyvita-min D as children who drank 2.85 cups (95% CI 2.71 to 2.99) of skim milk, but had zBMI score 0.78 (95% CI 0.63, 0.93) units lower.

CONCLUSION: Homogenized milk may be more appropriate than reduced fat milk in maximizing serum 25-hydroxyvitamin D and minimizing adiposity in early childhood. Current guidelines for reduced milk fat consumption in childhood may require further study to achieve desired outcomes.

How Well Does the Nipissing District Developmental Screen (NDDS) Identify Communication Problems in Infants?

BACKGROUND: Communication problems are often the first presenting problem in infants with developmental disabilities. With early detection, intervention can start. The 18-month Nipissing District Developmental Screen (NDDS) was created as a developmental checklist for use in primary care. The Infant Toddler Checklist (ITC) is a validated questionnaire for detecting communication problems. Our objective was to examine how well the 18-month NDDS identifies communication problems. We therefore assessed the convergent validity of the 18-month NDDS with the ITC as a gold standard.

OBJECTIVES: To examine how well the 18-month NDDS identifies communication problems. To compare parents’ answers to a similar question, “How many different words does your child use?”, on both checklists.

DESIGN/METHODS: Healthy children (n = 348, 55% male, mean age 18.6 months, SD 0.7) were recruited during scheduled health supervision visits. Parents completed both the 18-months NDDS and ITC. We assessed the convergent validity of the 18-month NDDS with the ITC as a gold standard. Correlation (Spearman) and the level of agreement (Cohen’s kappa, sensitivity, specificity) were calculated. For our secondary outcome, we compared the percentage of agreement between the answers to the same question on both instruments.

RESULTS: On the NDDS, 138 (39.7%) children had “one or more flags” (+1 NDDS) and 54 (15.8%) children had “two or more flags” (+2 NDDS). 13 (3.7%) infants had a concern on the total ITC score, 31 (8.9%) a speech-, 9 (2.6%) a social -, and 14 (4.0%) a symbolic concern.The +2 NDDS had a medium correlation (Spearman’s rho 0.42) and a fair agreement (Cohen’s kappa 0.32) with the ITC. Sensitivity and specificity of the NDDS using the +1 and + 2 flag cut-offs in detecting concerns compared with the ITC are shown in the table.The similar question about number of words spoken by 18-month old infants revealed agreement between the NDDS and ITC; 24.4% versus 30.8% of the 18-month old infants did not speak 20 words or more respectively.

CONCLUSION: Infants with a severe overall communication delay were identified with the 18-months NDDS. The low sensitivity of the 2+ NDDS flag in detecting speech and social concerns suggests that infants who could benefit from early interventions may not be identified.The low specificity of the 1+ NDDS flag may cause unnecessary concerns for parents.For the early identification of all levels of communicationdelays, we recommend using a standardized questionnaire like the ITC.

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Screening for Risk of Developmental Delay in a primary care setting using the Nippising District Developmental Screen

BACKGROUND: Early growth and development in the first five years of life is strongly associated with health outcomes. The Nipissing District Developmental Screen (NDDS) is a free parent-reported screening tool recommended by the Canadian Pediatric Society as one of the tools for developmental screening in children

OBJECTIVES: To determine the prevalence of a positive screen for risk of developmental delay in a cohort of healthy children at 18-months and 5 years. To identify risk factors (child, socio-demo-graphic and home environment) associated with a positive screen for risk of developmental delay.

DESIGN/METHODS: A cross-sectional study of healthy Canadian children attending 18-months and 5 year well-child visits between June 2008 and February 2015 was conducted through the TARGet Kids! practice-based research network. Multivariable logistic regression was used to identify risk factors associated with a positive screen for developmental delay. Risk factors of development delay identified from literature were:, male sex, low birth weight, low income, low maternal education, maternal unemployment, non-industrialized immigrant status, single parent family, only child and older maternal age.

RESULTS: 1086 children (53% male) at 18 months and 575 children (51% male) at 5 years were included in the final analysis. At 18 months, 341 (31.4%) of children (95% CI, 28.7% - 34.3%) and at 5 years 166 (28.9%) (95% CI, 25.2% -32.8%) were screen positive base on 1+ flag NDDS. At 18 months, children with a low birthweight (OR=1.66; 95% CI 1.22-2.28), with a mother with low education (OR=1.75; 95% CI 1.07-2.85), and those from non-industrialized immigrant families (OR=1.85; 95% CI 1.37-2.49) were associated with an increased odds of a positive screen for developmental delay based on the 1+ NDDS flag. A female child (OR=0.74; 95% CI 0.57-0.96) and an only child (OR=0.76; 95% CI 0.57-0.99) were associated with a decreased odds of a positive screen for developmental delay. At 5 years, factors associated with a positive screen for developmental delay based on the 1+ NDDS flag were: low maternal education (OR 2.24; 95% CI 1.14-4.39) (children had 2.24 times greater odds of a positive screen for developmental delay) and older maternal age (OR 1.05; 95% CI 1.00-1.09) (every 1-year increase in maternal age, children had 1.05 times greater odds of a positive screen for developmental delay). A female child was associated with a decreased odds of a positive screen for developmental delay (OR=0.66; 95% CI 0.46-0.96) based on the 1+ NDDS flag.

CONCLUSION: In a population of healthy urban children the NDDS identified 30% at both 18 month and 5 years at risk for developmental delay. Risk factors for developmental delay were associated with a positive NDDS screen.

Associations of circulating 25(OH)D with cardiometabolic disorders underlying type 2 diabetes mellitus in an Aboriginal Canadian community

AIMS

To investigate the associations of 25-hydroxyvitamin D (25(OH)D) with insulin resistance (IR), beta-cell function and metabolic syndrome (MetS) in a First Nations population.

METHODS

We conducted a cross-sectional analysis using data from the Sandy Lake Health and Diabetes Project (2003-2005). A total of 390 participants (>12 y) were assessed for 25(OH)D, fasting glucose, insulin, lipids, blood pressure, inflammatory markers, anthropometric and lifestyle variables and a 75-g oral glucose tolerance test was administered. IR was calculated using the Matsuda insulin sensitivity index (ISOGTT) and the computational homeostasis model assessment of IR (HOMA2-IR). Beta-cell function was calculated using the insulinogenic index (IGI) divided by HOMA-IR (IGI/IR) and the insulin secretion sensitivity index-2 (ISSI-2). The 2009 harmonized criteria were used to define MetS.

RESULTS

Higher 25(OH)D was associated with a decreased prevalence of dysglycemia (OR = 0.71 95% CI, 0.51-0.97 per SD increase). In addition, there were significant associations of 25(OH)D with measures of insulin action (ISOGTT; beta=0.31; 95% CI, 0.12, 0.49; HOMA2-IR; beta = -29; 95% CI -0.46, -0.11 and beta-cell function (ISSI-2; beta = 0.15; 95% CI, 0.02, 0.28). The prevalence of MetS was 41%. There was a decreased risk (OR=0.73, 95% CI 0.56, 0.94) of MetS per SD increase in baseline 25(OH)D. Finally, there was a significant positive association of 25(OH)D with adiponectin (beta = 0.16; 95% CI = 0.01, 0.31).

CONCLUSIONS

These results support a potential role for vitamin D metabolism in the natural history of T2DM among Aboriginal Canadians, although carefully designed randomized trials will be required to establish causality.