Evaluation of Increasing Dairy Intake on Bone Density in Postpubertal Youth: A Randomized Controlled Trial Using Motivational Interviewing.

BACKGROUND: Adequate nutrition is important for bone health, especially for bone mineral accretion. OBJECTIVES: The primary objective tested whether increasing dairy intake using the motivational interviewing technique (MInt) improves lumbar spine (LS) bone mineral density (BMD) after 2 y in postpubertal adolescents with habitual dairy intake of <2 dairy servings/d. METHODS: Participants (aged 14-18.9 y) were randomly allocated to: group 1 (control), group 2 (target of 3 dairy servings/d), or group 3 (target of ≥4 dairy servings/d) for 12 mo, with groups 2 and 3 using MInt, with an additional 12-mo nonintervention follow-up. The primary outcome was LS BMD, and secondary outcomes were: whole body, total hip (TH), and 33% distal radius BMD using DXA, bone geometry using peripheral quantitative computed tomography, and bone biomarkers. RESULTS: Ninety-four adolescents (16.6 ± 1.5 y) were recruited. Seventy-six (80.9%) completed the 12-mo assessments. From baseline to 12 mo, dairy intake in female groups 2 and 3 increased by 107% and 208%, respectively; and by 48% and 153% in males of groups 2 and 3, respectively. In females, group 3 had greater increases in TH BMD (4.3% to 7.5%) compared with control (3.7% to 4.9%, P = 0.04) and group 2 (0.0% to 1.7%, P = 0.04) at 12 and 24 mo. No effects due to dairy intake were observed for DXA outcomes in males for radial and tibial volumetric BMD in both sexes. None of the bone biomarkers were different among the dairy groups in females or males. CONCLUSIONS: MInt effectively increased dairy intake with benefits to bone health only in female adolescents with previously low calcium intake who consumed ≥4 dairy servings/d for 12 mo. Larger studies are required to explain the lack of intervention effect in males.

Evaluation of Increasing Dairy Intake on Bone Density in Postpubertal Youth: A Randomized Controlled Trial Using Motivational Interviewing.

BACKGROUND: Adequate nutrition is important for bone health, especially for bone mineral accretion. OBJECTIVES: The primary objective tested whether increasing dairy intake using the motivational interviewing technique (MInt) improves lumbar spine (LS) bone mineral density (BMD) after 2 y in postpubertal adolescents with habitual dairy intake of <2 dairy servings/d. METHODS: Participants (aged 14-18.9 y) were randomly allocated to: group 1 (control), group 2 (target of 3 dairy servings/d), or group 3 (target of ≥4 dairy servings/d) for 12 mo, with groups 2 and 3 using MInt, with an additional 12-mo nonintervention follow-up. The primary outcome was LS BMD, and secondary outcomes were: whole body, total hip (TH), and 33% distal radius BMD using DXA, bone geometry using peripheral quantitative computed tomography, and bone biomarkers. RESULTS: Ninety-four adolescents (16.6 ± 1.5 y) were recruited. Seventy-six (80.9%) completed the 12-mo assessments. From baseline to 12 mo, dairy intake in female groups 2 and 3 increased by 107% and 208%, respectively; and by 48% and 153% in males of groups 2 and 3, respectively. In females, group 3 had greater increases in TH BMD (4.3% to 7.5%) compared with control (3.7% to 4.9%, P = 0.04) and group 2 (0.0% to 1.7%, P = 0.04) at 12 and 24 mo. No effects due to dairy intake were observed for DXA outcomes in males for radial and tibial volumetric BMD in both sexes. None of the bone biomarkers were different among the dairy groups in females or males. CONCLUSIONS: MInt effectively increased dairy intake with benefits to bone health only in female adolescents with previously low calcium intake who consumed ≥4 dairy servings/d for 12 mo. Larger studies are required to explain the lack of intervention effect in males.

Disparities in Vitamin D Status of Newborn Infants from a Diverse Sociodemographic Population in Montreal, Canada.

BACKGROUND: Vitamin D status at birth is reliant on maternal-fetal transfer of vitamin D during gestation. OBJECTIVES: We aimed to examine the vitamin D status of newborn infants in a diverse population and to subsequently identify the modifiable correlates of vitamin D status. METHODS: In this cross-sectional study, healthy mother-infant dyads (n = 1035) were recruited within 36 h after term delivery (March 2016-March 2019). Demographic and lifestyle factors were surveyed. Newborn serum 25-hydroxyvitamin D [25(OH)D] was measured (standardized chemiluminescence immunoassay) and categorized as deficient [serum 25(OH)D <30 nmol/L] or adequate (≥40 nmol/L). Serum 25(OH)D was compared among categories of maternal characteristics using ANOVA; each characteristic was tested in a separate model. Subgroups (use of multivitamins preconception and continued in pregnancy compared with during pregnancy only) were matched (n = 352/group) for maternal factors (ancestry, age, income, education, parity, and prepregnancy BMI) using propensity scores; logistic regression models were generated for odds of deficiency or adequacy. RESULTS: Infants' mean serum 25(OH)D was 45.9 nmol/L (95% CI: 44.7, 47.0 nmol/L) (n = 1035), with 20.8% (95% CI: 18.3%, 23.2%) deficient and 60.7% (95% CI: 55.2%, 66.2%) adequate. Deficiency prevalence ranged from 14.6% of white infants to 41.7% of black infants. Serum 25(OH)D was higher (P < 0.0001) in infants of mothers with higher income, BMI < 25 kg/m2, exercise and sun exposure in pregnancy, and use of multivitamins preconception. In the matched-subgroup analysis, multivitamin supplementation preconception plus during pregnancy relative to only during pregnancy was associated with lower odds for vitamin D deficiency (ORadj: 0.55; 95% CI: 0.36, 0.86) and higher odds for adequate vitamin D status (ORadj: 1.47; 95% CI: 1.04, 2.07). CONCLUSIONS: In this study most newborn infants had adequate vitamin D status, yet one-fifth were vitamin D deficient with disparities between population groups. Guidelines for a healthy pregnancy recommend maternal use of multivitamins preconception and continuing in pregnancy. An emphasis on preconception use may help to achieve adequate neonatal vitamin D status.This trial was registered at clinicaltrials.gov as NCT02563015.

Vitamin D Status of Infants of Mothers with Gestational Diabetes: Status at Birth and a Randomized Controlled Trial of Vitamin D Supplementation across Infancy.

BACKGROUND: Vitamin D status and requirements of infants of women with gestational diabetes mellitus (GDM) are unclear. OBJECTIVES: The objectives were to assess vitamin D status in infants of mothers with GDM and compare vitamin D status in response to 400 vs. 1000 IU/d vitamin D supplementation in infants born with serum 25-hydroxyvitamin D [25(OH)D] <50 nmol/L. METHODS: Women with GDM delivering full-term infants (n = 98; March 2017-2019, Montreal, Canada) were surveyed for demographic and lifestyle factors. Pregnancy history was obtained from medical records. Newborn serum 25(OH)D was measured (immunoassay) and categorized as <30 (deficient) or ≥40 nmol/L (adequate). Breastfed neonates (n = 16) with serum 25(OH)D <50 nmol/L at birth were randomly assigned to 400 or 1000 IU/d of supplemental cholecalciferol (vitamin D3), and serum 25(OH)D was measured at baseline (≤1 mo) and 3, 6, and 12 mo of age. Groups were compared using a linear mixed-effects model and Tukey-Kramer post hoc tests. RESULTS: Mean newborn serum 25(OH)D was 46.4 (95% CI: 43.9, 49.9) nmol/L, with 15.3% (95% CI: 8.2%, 22.4%) <30 nmol/L and 61.2% (95% CI: 51.6%, 70.9%) ≥40 nmol/L. During the trial, most infants were breastfed to 3 mo (400 IU/d: 87.5%; 1000 IU/d: 75.0%). Mean (± SEM) infant serum 25(OH)D was higher in the 1000-IU/d group at 3 mo (79.9 ± 5.9 vs. 111.5 ± 15.2 nmol/L; P = 0.0263), and although not different at 6-12 mo, was maintained at >50 nmol/L. CONCLUSIONS: Most infants of women with GDM had adequate vitamin D status in this study. In those born with serum 25(OH)D <50 nmol/L, vitamin D status was corrected by 3 mo of age in response to 400 or 1000 IU/d of supplemental vitamin D. Dietary guidance should continue to recommend that all women who could become pregnant take a multivitamin supplement and that breastfed infants receive 400 IU/d of supplemental vitamin D. This study and ancillary trial were registered at clinicaltrials.gov (https://www. CLINICALTRIALS: gov/ct2/show/NCT02563015) as NCT02563015.

Maternal excess adiposity and serum 25-hydroxyvitamin D < 50 nmol/L are associated with elevated whole body fat mass in healthy breastfed neonates.

BACKGROUND: Vitamin D status of pregnant women is associated with body composition of the offspring. The objective of this study was to assess whether the association between maternal vitamin D status and neonatal adiposity is modified by maternal adiposity preconception. METHODS: Healthy mothers and their term appropriate weight for gestational age (AGA) infants (n = 142; 59% male, Greater Montreal, March 2016-2019) were studied at birth and 1 month postpartum (2-6 weeks). Newborn (24-36 h) serum was collected to measure total 25-hydroxyvitamin D [25(OH)D] (immunoassay); maternal pre-pregnancy BMI was obtained from the medical record. Anthropometry, body composition (dual-energy X-ray absorptiometry) and serum 25(OH)D were measured at 2-6 weeks postpartum in mothers and infants. Mothers were grouped into 4 categories based on their vitamin D status (sufficient 25(OH)D ≥ 50 nmol/L vs. at risk of being insufficient < 50 nmol/L) and pre-pregnancy BMI (< 25 vs. ≥25 kg/m2): insufficient-recommended weight (I-RW, n = 24); insufficient-overweight/obese (I-OW/O, n = 21); sufficient-recommended weight (S-RW, n = 69); and sufficient-overweight/obese (S-OW/O, n = 28). Partial correlation and linear fixed effects model were used while adjusting for covariates. RESULTS: At birth, infant serum 25(OH)D mean concentrations were below 50 nmol/L, the cut-point for sufficiency, for both maternal pre-pregnancy BMI categories; 47.8 [95%CI: 43.8, 51.9] nmol/L if BMI < 25 kg/m2 and 38.1 [95%CI: 33.5, 42.7] nmol/L if BMI ≥25 kg/m2. Infant serum 25(OH)D concentrations at birth (r = 0.77; P < 0.0001) and 1 month (r = 0.59, P < 0.0001) were positively correlated with maternal postpartum serum 25(OH)D concentrations. Maternal serum 25(OH)D concentration was weakly correlated with maternal percent whole body fat mass (r = - 0.26, P = 0.002). Infants of mothers in I-OW/O had higher fat mass versus those of mothers in S-OW/O (914.0 [95%CI: 766.4, 1061.6] vs. 780.7 [95%CI: 659.3, 902.0] g; effect size [Hedges' g: 0.42]; P = 0.04 adjusting for covariates) with magnitude of difference of 220.4 g or ~ 28% difference. CONCLUSIONS: Maternal and neonatal vitamin D status are positively correlated. In this study, maternal adiposity and serum 25(OH)D < 50 nmol/L are dual exposures for neonatal adiposity. These findings reinforce the importance of vitamin D supplementation early in infancy irrespective of vitamin D stores acquired in utero and maternal weight status.

Patterns of Bone Mineral Accretion and Sex Differences in Healthy Term Vitamin D Replete and Breastfed Infants From Montreal, Canada: Bone Mass Reference Data.

Infancy is a period of rapid bone growth and mineral accretion; nonetheless, reference data remain scarce for this age group. The purpose of this report is to generate reference data for bone mass in breastfed vitamin D replete infants and investigate patterns of bone mineral accretion and sex differences. This is a secondary analysis from a double-blinded randomized controlled trial (NCT00381914). Healthy term breastfed (exclusively or mixed) infants were randomized to different doses of oral vitamin D supplementation (400-1600 IU/d) and followed prospectively from 1 to 12 mo. Plasma 25-hydroxyvitamin D (LC-MS/MS), bone mineral content (BMC; whole body (WB) and lumbar spine (LS)) and bone mineral density (BMD; LS) were measured at 1, 3, 6, 9, and 12 mo by dual-energy x-ray absorptiometry (Hologic Discovery 4500A) with no effect of supplementation on bone outcomes. For the purpose of this analysis, 63 infants with adequate plasma 25-hydroxyvitamin D ≥ 50 nmol/L at baseline, were included. Differences over time and between sexes were tested using mixed model repeated measures ANOVA. Infants (31 males, 32 females) were 39.5 ± 1.1 wk gestational age at birth and appropriate for gestational age. WB BMC, LS BMC, and LS BMD increased by 143.2%, 116.8%, and 31.1% respectively across infancy. WB BMC was higher (4.2% - 9.4%; p = 0.03) in males than in females across the study. After adjusting WB BMC for weight, length or head BMC, sex differences were not evident. LS BMC and LS BMD did not vary by sex. LS BMD growth charts for both sexes combined, were generated using LMS chartmaker. WB BMC more than doubles during the first year of life confirming the importance of skeletal growth and the need for age-specific reference data in infancy. Sex differences in BMC, if any, are mostly driven by differences in body size.

Normative Data for Lean Mass and Fat Mass in Healthy Predominantly Breast-Fed Term Infants From 1 Month to 1 Year of Age.

BACKGROUND: A leaner body phenotype in infancy plays an important role in the early life prevention of obesity. However, there is a dearth of reference data for body composition in infancy. This study aimed to create a normative reference dataset for lean (LM) and fat (FM) mass and accretion rates in healthy infants. METHODS: Healthy term-born infants (35 boys; 35 girls) were studied at ≤ 1, 3, 6, 9, and 12 mo of age for growth and compared to World Health Organization standards. LM (g) and FM (g) were measured using DXA (APEX version 13.3:3, Hologic 4500A) in infant whole-body mode. Sex specific reference curves were generated using the LMS method (LMSchartmaker, Medical Research Council, UK). RESULTS: Infants were predominantly white (82.9%), breastfed (98.4% ≥ 3 mo), and grew in length and weight within World Health Organization Z-score ranges for normal growth across infancy. LM accretion was 327.4 ± 12.5 g/mo representing 95% increment in LM. Boys had more LM compared to girls at 12 mo (7807.4 ± 1114.0 vs 6817.4 ± 1016.1 g; p = 0.008). FM accretion was 114.3 ± 12.0 g/mo representing 114% increment in FM with no difference between the sexes. CONCLUSIONS: This data, which is based on a healthy sample of infants, characterizes LM and FM accretion during the first year of life and will aid in the interpretation of body composition.

Changes in eating behavior and plasma leptin in children with obesity participating in a family-centered lifestyle intervention.

The goal of childhood obesity lifestyle interventions are to positively change body composition, however it is unknown if interventions also modulate factors that are related to energy intake. This study aimed to examine changes in eating behaviors and plasma leptin concentrations in overweight and obese children participating in a 1-year family-centered lifestyle intervention. Interventions were based on Canadian diet and physical activity (PA) guidelines. Children were randomized to 1 of 3 groups: Control (Ctrl; no intervention), Standard treatment (StnTx: 2 servings milk and alternatives/day (d), 3x/wk weight-bearing PA), or Modified treatment (ModTx: 4 servings milk and alternatives/day; daily weight-bearing PA). Study visits occurred every 3-months for 1-y; interventions were held once a month for 6-months with one follow-up visit at 8-months. Ctrl received counselling after 1-y. Caregivers completed the Children's Eating Behavior Questionnaire (CEBQ) and reported on diet and activity. Plasma leptin were measured from morning fasted blood samples. Seventy-eight children (mean age 7.8 ±â€¯0.8 y; mean BMI 24.4 ±â€¯3.3 kg/m2) participated; 94% completed the study. Compared to baseline, at 6-months StnTx reduced Emotional Overeating and Desire to Drink scores (p < 0.05) while Food Responsiveness scores were reduced in both StnTx and ModTx (p < 0.05). At 1-year, scores for Desire to Drink in StnTx remained reduced compared to baseline (p < 0.05). Plasma leptin concentrations were significantly lower in ModTx at 6-months compared to baseline (p < 0.05). This study resulted in intervention groups favorably changing eating behaviors, supporting the use family-centered lifestyle interventions using Canadian diet and PA recommendations for children with obesity.

Bone Health is Maintained, While Fat Mass is Reduced in Pre-pubertal Children with Obesity Participating in a 1-Year Family-Centered Lifestyle Intervention.

Diet and physical activity (PA) influence bone health in children. This study tested whether increasing milk and milk products and weight-bearing types of PA favorably changed bone outcomes assessed by dual-energy X-ray absorptiometry (DXA) and bone biomarkers in children with obesity participating in a 1-year family-centered lifestyle intervention. Children were randomized to one of three groups: Control (Ctrl; no intervention), Standard treatment (StnTx: two servings milk and milk products/day; meet PA guidelines plus weight-bearing PA three times/week), or Modified treatment (ModTx: four servings milk and milk products/day; meet PA guidelines plus daily weight-bearing PA). Baseline and 12-month measurements included DXA scans for whole body (WB), lumbar spine (LS), lumbar lateral spine (LLS), and ultra-distal (UD) ulna + radius for bone mineral content (BMC), areal bone mineral density (aBMD) and BMD z-scores. Fat mass index (FMI), fat-free mass index (FFMI), and biomarkers of bone metabolism were assessed. Seventy-eight children 6-8 years old were recruited (mean body mass index for-age z-score: 3.3 ± 1.2). Compared to baseline, all groups increased BMC of WB, LS, and LLS (p < 0.001), whereas only StnTx increased UD ulna + radius BMC at 12 months (p < 0.05). At 12 months, WB-BMD z-scores were significantly lower in Ctrl (p < 0.05), whereas WB and LLS aBMD increased in StnTx and ModTx (p < 0.001) but not in Ctrl. All groups increased FFMI (p < 0.001), while only Ctrl increased FMI (p < 0.001). Bone biomarkers did not change over time. Participating in a family-centered lifestyle intervention based on Canadian diet and PA guidelines maintained bone health in obese children.

Assessment of pedometer accuracy in capturing habitual types of physical activities in overweight and obese children.

BACKGROUND: Currently, there is a limited amount of research exploring physical activity measurement tools in overweight and obese (OW/OB) children using pedometers. Thus, our objective was to determine the accuracy of one spring-levered (SC-T2) and two piezoelectric pedometers (NL-1000 and Piezo) in OW/OB children. METHODS: A total of 26 boys and 34 girls (n = 60) participated. Pedometer step-counts were compared to observed step counts for walking (walking, stair ascent and decent) and hopping tests. Pedometer accuracies were compared with Friedman tests while Bland-Altman plots were used to establish the accuracy of each pedometer against direct observations. RESULTS: Boys (n = 26) and females (n = 34) were 96 and 91% OB, respectively. The two piezoelectric pedometers (NL-1000 and Piezo) were accurate for walking and stair climbing tasks, however all pedometers were inaccurate for hopping tests. Averaged over all three walking activities, the NL-1000 was the most accurate with 6.7% median error (interquartile range (IQR): 0.0-13.3); followed by the Piezo with 10.0% median error (IQR: 3.3-18.1); SC-T2 was the least accurate with -14.7% median error (IQR: -54.8-3.5). CONCLUSION: These results support the use of the piezoelectric pedometers for walking and stair climbing types of activities, which are typical for OW/OB children in a nonlaboratory setting.

Vitamin D status is associated with bone mineral density and bone mineral content in preschool-aged children.

This study examined the associations between vitamin D status, bone mineral content (BMC), areal bone mineral density (aBMD), and markers of calcium homeostasis in preschool-aged children. Children (n=488; age range: 1.8-6.0 y) were randomly recruited from Montreal. The distal forearm was scanned using a peripheral dual-energy X-ray absorptiometry scanner (Lunar PIXI; GE Healthcare, Fairfield, CT). A subset (n=81) had clinical dual-energy X-ray absorptiometry (cDXA) scans (Hologic 4500A Discovery Series) of lumbar spine (LS) 1-4, whole body, and ultradistal forearm. All were assessed for plasma 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone concentrations (Liaison; Diasorin), ionized calcium (ABL80 FLEX; Radiometer Medical A/S), and dietary vitamin D and calcium intakes by survey. Age (p<0.001) and weight-for-age Z-score (p<0.001) were positively associated with BMC and aBMD in all regression models, whereas male sex contributed positively to forearm BMC and aBMD. Having a 25(OH)D concentration of >75 nmol/L positively associated with forearm and whole body BMC and aBMD (p<0.036). Sun index related to (p<0.029) cDXA forearm and LS 1-4 BMC and whole-body aBMD. Nutrient intakes did not relate to BMC or aBMD. In conclusion, higher vitamin D status is linked to higher BMC and aBMD of forearm and whole body in preschool-aged children.

The change in plasma 25-hydroxyvitamin D did not differ between breast-fed infants that received a daily supplement of ergocalciferol or cholecalciferol for 3 months.

The biological equivalency of ergocalciferol (D2) and cholecalciferol (D3) has been debated; several comparisons have appeared in the adult literature but are scarce in pediatrics. The objective of this study was to compare increases in plasma 25-hydroxyvitamin D [25(OH)D] concentrations and attainment of 50 and 75 mol/L status cutoffs following 3 mo of daily supplementation with D2 compared with D3. Healthy, breast-fed, 1-mo-old infants (n = 52) received 10 µg (400 ic) of either D2 or D3 daily. At 1 and 4 mo of age, plasma 25-hydroxyergocalciferol and 25-hydroxycholecalciferol concentrations were determined by liquid chromatography tandem MS (LC-MS/MS) and total 25(OH)D by chemiluminescent immunoassay (DiaSorin Liaison). Data were analyzed using t tests and χ² by intent to treat. A total of 23% of infants were deficient (≤24.9 nmol/L) at baseline and 2% at follow-up on the basis of LC-MS/MS. At 4 mo, 96% were breastfed and there were no differences in compliance, breastfeeding rates, or sun exposure among groups. The change in total 25(OH)D measured by LC-MS/MS did not differ between the D2 (17.6 ± 26.7 nmol/L) and D3 (22.2 ± 20.2 nmol/L) groups. In the combined groups, the baseline plasma 25(OH)D concentration was inversely related to the change in total 25(OH)D (r = -0.52; P < 0.001). Overall, 86% of infants met the 50 nmol/L cutoff at follow-up; however, fewer infants in the D2 group (75%) met this level compared with the D3 group (96%) (P < 0.05). Similar results were obtained by immunoassay. In conclusion, the increase in the 25(OH)D concentration among the D2 and D3 groups did not differ, suggesting daily intake of either isoform is acceptable for infants <4 mo.

Vitamin D status in Montréal preschoolers is satisfactory despite low vitamin D intake.

The 2007 to 2009 Canadian Health Measures Survey reported vitamin D status in a representative sample of Canadians (6-79 y); however, children <6 y were not assessed. Our objective was to measure vitamin D intake from food and supplements, sun exposure, and biological vitamin D status of children ages 2 through 5 y in Montréal (latitude 45°N). Preschoolers (n = 508) were recruited between June 2010 and 2011 in a random sample of licensed daycares in the regions of greater Montréal, Canada in a cross-sectional study. The total plasma 25-hydroxyvitamin D [25(OH)D] concentration was measured using a chemiluminescence assay (Liaison, Diasorin). Dietary intake was assessed during one 24-h period plus a 30-d FFQ. Socioeconomic, demographic, anthropometry, and sun exposure data were collected. Plasma 25(OH)D was ≥50 nmol/L in 88% of children, whereas 49.4% had concentrations ≥75 nmol/L during the 1-y study. Almost 95% of preschoolers had vitamin D intakes less than the Estimated Average Requirement (EAR), and 4.8% of preschoolers ≤3.9 y and 25.9% of preschoolers ≥4 y had calcium intakes less than the EAR. Plasma 25(OH)D was different across age, income, sun index, milk intake, and dietary and supplemental vitamin D intake tertiles. Despite vitamin D intakes less than the EAR, the vitamin D status of Montréal preschoolers attending daycare is mostly satisfactory even in winter, suggesting that the EAR value is too high in the context of typical exogenous intakes of vitamin D in North America.

Bone mineral density measured by a portable X-ray device agrees with dual-energy X-ray absorptiometry at forearm in preschool aged children.

Dual-energy X-ray absorptiometry (DXA) measures of bone mineral density (BMD) are generally not feasible in fieldwork. The present study determined the agreement between BMD measured by DXA and portable peripheral DXA in preschool aged children. Fifty-seven children (4.2 ± 1.0 yr) had their nondominant distal forearm scanned using a peripheral DXA scanner (PIXI; GE Medical Systems Lunar, Madison, WI) at their daycare and a DXA (4500A Discovery Series; Hologic Inc., Bedford, MA) at our research clinic. Correlation analysis, one-way analysis of variance, and Bland-Altman plots were performed to examine the agreement between measurements. Data were also divided into tertiles for cross-classification analysis and calculation of kappa coefficients. Distal forearm BMD measured by PIXI was significantly correlated with DXA measures of total forearm BMD (r > 0.51; p < 0.001), proximal 1/3 BMD (r > 0.41; p < 0.001), mid-BMD (r > 0.37; p < 0.001), and ultradistal (UD) BMD (r > 0.57; p < 0.001). Cross-classification in the same or adjacent tertile between measures (UD forearm: 96.5%; UD radius: 94.4%; total forearm: 87.7%; total radius: 84.2%) resulted in weighted kappa coefficients of 0.46, 0.58, 0.42, and 0.43, respectively. Bland-Altman plots further clarified these agreements as all had low bias (UD forearm: bias = 0.003 ± 0.002; UD radius: -0.015 ± 0.021; total forearm: -0.062 ± 0.027; total radius: -0.077 ± 0.026). These results demonstrate that portable DXA measures of forearm BMD agree moderately with DXA.

A family-centered lifestyle intervention to improve body composition and bone mass in overweight and obese children 6 through 8 years: a randomized controlled trial study protocol.

BACKGROUND: Childhood obesity gives rise to health complications including impaired musculoskeletal development that associates with increased risk of fractures. Prevention and treatment programs should focus on nutrition education, increasing physical activity (PA), reducing sedentary behaviours, and should monitor bone mass as a component of body composition. To ensure lifestyle changes are sustained in the home environment, programs need to be family-centered. To date, no study has reported on a family-centered lifestyle intervention for obese children that aims to not only ameliorate adiposity, but also support increases in bone and lean muscle mass. Furthermore, it is unknown if programs of such nature can also favorably change eating and activity behaviors. The aim of this study is to determine the effects of a 1 y family-centered lifestyle intervention, focused on both nutrient dense foods including increased intakes of milk and alternatives, plus total and weight-bearing PA, on body composition and bone mass in overweight or obese children. METHODS/DESIGN: The study design is a randomized controlled trial for overweight or obese children (6-8 y). Participants are randomized to control, standard treatment (StTx) or modified treatment (ModTx). This study is family-centred and includes individualized counselling sessions on nutrition, PA and sedentary behaviors occurring 4 weeks after baseline for 5 months, then at the end of month 8. The control group receives counselling at the end of the study. All groups are measured at baseline and every 3 months for the primary outcome of changes in body mass index Z-scores. At each visit blood is drawn and children complete a researcher-administered behavior questionnaire and muscle function testing. Changes from baseline to 12 months in body fat (% and mass), waist circumference, lean body mass, bone (mineral content, mineral density, size and volumetric density), dietary intake, self-reported PA and sedentary behaviour are examined. DISCUSSION: This family-centered theory-based study permits for biochemical and physiological assessments. This trial will assess the effectiveness of the intervention at changing lifestyle behaviours by decreasing adiposity while enhancing lean and bone mass. If successful, the intervention proposed offers new insights for the management or treatment of childhood obesity. TRIAL REGISTRATION: ClinicalTrials.gov, NCT01290016.

Parathyroid hormone-vitamin D dynamics vary according to the definition of vitamin D deficiency in newborn infants.

BACKGROUND: Parathyroid hormone (PTH) is an indirect functional indicator of vitamin D status. Risk of vitamin D deficiency, assessed using circulating 25-hydroxyvitamin D (25(OH)D), is defined as <30 nmol/L by the National Academy of Medicine and alternatively <25 nmol/L in the global consensus recommendation on prevention and management of nutritional rickets. OBJECTIVE: To test PTH concentrations and the odds for elevated values according to vitamin D deficiency cut-points (<30 nmol/L, or <25 nmol/L) in newborn infants. METHODS: Healthy term-born infants (n = 858) were recruited from Montreal, Canada (2016-2019). Obstetric data were obtained from medical records, and demographic factors surveyed. Immunoassays were used to measure newborn (24-36 h) serum PTH and 25(OH)D; 25(OH)D was standardized to National Institute of Standards and Technology (NIST) standard reference materials. Serum PTH was log-transformed before comparing serum 25(OH)D groups (<30 vs. ≥30; or <25 vs. ≥25 nmol/L) using ANCOVA adjusted for infant sex, type of delivery, parity, race, and family income. The odds of elevated PTH (>71.48 pg/mL) were tested using logistic regression, adjusted for the same covariates. RESULTS: Infants (50.2 % female) were 39.6 ± 1.0 weeks gestational age (mean ± SD), and 3.41 ± 0.38 kg. Median serum 25(OH)D was 45.4 (IQR 23.2) nmol/L; 20.5 % had serum 25(OH)D < 30 nmol/L, and 12.4 % <25 nmol/L. Median serum PTH was 30.72 (IQR 33.90) pg/mL, elevated in 12.7 % overall, and higher in infants born with serum 25(OH)D < 25 vs. ≥25 nmol/L (35.96 (IQR 39.20) vs. 30.36 (IQR 32.93) pg/mL, p = 0.0158). The odds of elevated PTH were higher when serum 25(OH)D was <25 nmol/L (ORadj 2.13, 95 % CI: 1.23, 3.69). PTH concentration and the odds of being elevated did not differ according to the 30 nmol/L cut-point. CONCLUSIONS: Based on this study, the definition of vitamin D deficiency relative to bone health as set by the National Academy of Medicine (<30 nmol/L) exceeds the threshold at which PTH is elevated in newborn infants.

Changes in Adiposity without Impacting Bone Health in Nine- to Twelve-Year-Old Children with Overweight and Obesity after a One-Year Family-Centered Lifestyle Behavior Intervention.

Background: Few family-centered lifestyle interventions (FCLIs) for children with overweight or obesity (OW/OB) have assessed regional adiposity and bone health. This study assessed changes in adiposity in 9- to 12-year olds with OW/OB in a 1-year FCLI. Methods: Children were randomized to FCLI (six registered dietitian-led sessions) or no intervention (Control, CTRL). The FCLI focused on physical activity, nutrition education, and behavioral counseling children with families present. Assessments occurred at baseline and every 3 months for 1 year to assess changes in waist circumference (WC), body mass index for age-and-sex Z-scores (BAZ), body composition (dual-energy x-ray absorptiometry), and cardiometabolic biomarkers. Mixed models were used to determine the effects of group and time or group-by-time interactions for all outcomes. Results: Sixty children (age: 11.1 ± 1.1 years, BAZ: 2.7 ± 0.6) were enrolled; 55 participants (n = 28 CTRL, n = 27 FCLI) completed the study. There were no between group differences from baseline to follow-up for any measure. The FCLI group had significant decreases in BAZ over 12 months (-0.18 ± 0.27, p = 0.03) but not CTRL (-0.05 ± 0.32, p = 0.92). WC and android fat mass did not change in FCLI (p > 0.20) but increased in CTRL (p < 0.02). Whole body bone area, content, and areal bone mineral density (aBMD) increased in both groups (p < 0.010); whole body aBMD Z-score decreased by 5.8% and 1.6% in CTRL and FCLI, respectively (p < 0.001). There were no significant within group changes in biomarkers. Conclusion: The FCLI resulted in small reductions in BAZ and a plateau in android fat mass, which suggest that FCLIs are suitable as an intervention for 9- to 12-year-old children with OW/OB. Clinical Trial Registration number: NCT01290016.

Effect of Vitamin D Supplementation on Bone Mass in Infants With 25-Hydroxyvitamin D Concentrations Less Than 50 nmol/L: A Prespecified Secondary Analysis of a Randomized Clinical Trial.

Importance: The dose of supplemental vitamin D needed in infants born with serum 25-hydroxyvitamin D (25[OH]D) concentrations less than 50 nmol/L (ie, 20 ng/mL) is unclear. Objective: To determine whether a higher dose (1000 IU vs 400 IU per day) is required in infants born with 25(OH)D concentrations less than 50 nmol/L for bone mineral accretion across infancy. Design, Setting, and Participants: In this prespecified secondary analysis of a double-blinded randomized clinical trial, conducted from March 2016 to March 2019 in a single center in Greater Montreal, Quebec, Canada, a consecutive sample of 139 healthy term singletons were recruited from 866 infants screened for vitamin D status at birth. Data were analyzed from June 2021 to November 2022. Interventions: Capillary blood was collected 24 to 36 hours after birth to measure serum total 25(OH)D concentrations. Infants with 25(OH)D concentrations less than 50 nmol/L were randomized to receive either 1000 IU or 400 IU per day of oral vitamin D3 supplementation from age 1 to 12 months. Infants with 25(OH)D concentrations of 50 nmol/L or greater formed a reference group. Main Outcomes and Measures: Measures at age 1, 3, 6, and 12 months were preplanned and included whole-body bone mineral content, lumbar spine bone mineral content, and bone mineral density using dual-energy x-ray absorptiometry, and serum 25(OH)D3 using liquid chromatography tandem mass spectrometry. Results: Of 139 included infants, 81 (58.3%) were male, and the median (IQR) gestational age at birth was 39.6 (38.9-40.6) weeks. A total of 49 infants were included in the 1000 IU per day group, 49 infants in the 400 IU per day group, and 41 in the reference group. Mean (SD) whole-body bone mineral content was not different between trial groups over time (1000 IU per day, 173.09 [2.36] g; 400 IU per day, 165.94 [66.08] g). Similarly, no differences were observed in lumbar spine bone mineral content or density. Mean (SD) serum 25(OH)D3 concentrations were significantly higher in the 1000 IU per day group from age 3 to 12 months (3 months, 115.2 [35.3] nmol/L; 6 months, 121.6 [34.4] nmol/L; 12 months, 99.6 [28.8] nmol/L) compared with the 400 IU per day trial group (3 months, 77.4 [23.3] nmol/L; 6 months, 85.1 [18.6] nmol/L; 12 months, 82.3 [14.3] nmol/L). Conclusions and Relevance: In this study, a higher dose of vitamin D supplementation in infants born with 25(OH)D concentrations less than 50 nmol/L did not present advantages to bone mass in infancy. This study supports a standard dose of 400 IU per day of vitamin D supplementation for breastfed infants in Montreal. Trial Registration: ClinicalTrials.gov Identifier: NCT02563015.

Vitamin D supplementation and gross motor development: A 3-year follow-up of a randomized trial.

BACKGROUND: Vitamin D status during pregnancy, early childhood and season-at-birth are implicated in gross motor development (GMD). AIM: To test whether vitamin D intake in infancy and season-at-birth affect GMD in early childhood. STUDY DESIGN: 3-year follow up study of a single-center trial. SUBJECTS: Healthy infants (n = 116) were allocated to 400 (standard-of-care), 800 or 1200 IU/day of vitamin D3 supplementation from 1 to 12 months; n = 70 returned for follow-up at 3-years. OUTCOME MEASURES: The main outcome was GMD using the Peabody Developmental Motor Scales-2 which includes gross motor quotient (GMQ) and stationary, locomotion and object manipulation subtests. RESULTS: GMQ scores were normal (≥85) in 94 %. An interaction between dosage group and season-at-birth (p = 0.01) was observed for GMQ and stationary standardized score; among winter/spring born children, the 1200 IU/d scored higher vs. 400 and 800 IU/d groups. Object manipulation standardized score was higher (p = 0.04) in children in the 1200 vs. 400 IU/d group, without interaction with season-at-birth. CONCLUSIONS: GMD in young children who received 400 IU/d of supplemental vitamin D in infancy is not influenced by season-at-birth. This dose of vitamin D of 400 IU/d as recommended in North America adequately supports GMD. The modest enhancement in GMD with 1200 IU/d in winter/spring born children requires further study.

Associations between Body Composition and Vitamin D Status in Children with Overweight and Obesity Participating in a 1-Year Lifestyle Intervention.

Background: To examine associations between body composition and vitamin D status in children participating in a lifestyle intervention. Methods: Children (6−12 y, n = 101) with a body mass index (BMI)-for-age >85th percentile were randomized to six dietitian-led behavior counselling sessions or no intervention. Plasma 25-hydroxyvitamin D (25(OH)D), anthropometry, and body composition using dual-energy X-ray absorptiometry were assessed every 3 months for 1 year. For each anthropometry variable (z-scores), tertiles were created to test for differences in 25(OH)D over time (tertile-by-time), and for changes in the z-score (loss, maintain, gain)-by-time, and according to fat patterning (android vs. gynoid) using mixed effects models. Results: The baseline plasma 25(OH)D was 62.2 nmol/L (95%CI: 58.7−65.7), and none < 30 nmol/L. At 6 mo, children with gynoid fat patterning had higher 25(OH)D concentrations than in those with android fat patterning (64.5 ± 1.1 nmol/L vs. 50.4 ± 1.0 nmol/L, p < 0.003, Cohen's f = 0.20). Children with the lowest lean mass index z-score at 9 mo had higher plasma 25(OH)D concentrations than children with the highest z-score at baseline, 3 mo, and 6 mo (p < 0.05, Cohen's f = 0.20). No other significant differences were observed. Conclusion: In this longitudinal study, vitamin D deficiency was not present in children 6−12 y of age with obesity. Reductions in adiposity did not alter the vitamin D status.