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.

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.

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.

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.

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.