The timing and quality of sleep was associated with dietary quality and anthropometry in toddlers born preterm

AIM

The aim of the study was to examine prospective associations of sleep characteristics (duration, timing, quality) with dietary and anthropometric measures among toddlers born preterm (<35 weeks).

METHODS

Children participated in the Omega Tots trial at 10-17 months' corrected age (Ohio, USA; 26 April 2012 to 6 April 2017). Caregivers reported toddlers' sleep at baseline using the Brief Infant Sleep Questionnaire. After 180 days, caregivers reported toddlers' past month diet in a food frequency questionnaire, and anthropometry was measured using standardised protocols. The toddler diet quality index (TDQI: higher scores indicating better quality), and weight-for-length, triceps skinfold and subscapular skinfold z-scores were calculated. Linear and logistic regression assessed adjusted associations with dietary and anthropometric outcomes at 180-day follow-up (n = 284), and linear mixed models assessed changes in anthropometry.

RESULTS

Daytime sleep was associated with lower TDQI (β_adj per hour = -1.62 (95% CI: -2.71, -0.52)) whereas night-time sleep was associated with higher TDQI (β_adj  = 1.01 (95% CI: 0.16, 1.85)). Night-time awakenings and caregiver-reported sleep problems were also associated with lower TDQI. Night awakening duration and sleep-onset latency were associated with higher triceps skinfold z-score.

CONCLUSION

Daytime and night-time caregiver-reported sleep showed opposite associations with diet quality, suggesting that sleep timing may be important.

Mild Idiopathic Infantile Hypercalcemia-Part 2: A Longitudinal Observational Study

CONTEXT

Idiopathic infantile hypercalcemia (IIH) is an uncommon disorder with variable clinical features. The natural history and response to dietary calcium and vitamin D restriction in IIH remains unclear.

OBJECTIVE

The aim of this study is to describe the clinical and biochemical response to dietary calcium and vitamin D restriction in a genetically characterized cohort of mild IIH.

METHODS

This is a longitudinal, observational cohort study of 20 children with mild IIH monitored for a median of 21months. Biochemical measures, dietary assessment, and yearly renal ultrasound results, since the time of diagnosis, were obtained and assessed prospectively every 4 to 6 months.

RESULTS

Median age at initial diagnosis was 4.5 months. Median levels of serum calcium (2.82 mmol/L) and 1,25 (OH)2D (192 pmol/L) were elevated, whereas serum PTH was reduced (10 ng/L). Urinary calcium:creatinine ratio was elevated for some, but not all individuals (median 1.49 mmol/mmol). All patients who were managed with a low-calcium diet showed an improvement in serum and urinary calcium measures, but the serum concentration of 1,25 dihydroxyvitamin D (1,25(OH)2D) and 1,25(OH)2D/PTH ratio remained elevated. In 2 of the 11 subjects, renal calcification worsened. There were no differences in response between individuals with CYP24A1 or SLC34A1/A3 variants.

CONCLUSION

The clinical presentation of mild IIH is variable, and dietary calcium and vitamin D restriction does not consistently normalize elevated 1,25(OH)2D concentrations or prevent worsening of renal calcification in all cases. Therapeutic options should target the defect in vitamin D metabolism.

Mild Idiopathic Infantile Hypercalcemia-Part 1: Biochemical and Genetic Findings

CONTEXT

Idiopathic infantile hypercalcemia (IIH), an uncommon disorder characterized by elevated serum concentrations of 1,25 dihydroxyvitamin D (1,25(OH)2D) and low parathyroid hormone (PTH) levels, may present with mild to severe hypercalcemia during the first months of life. Biallelic variants in the CYP24A1 or SLC34A1 genes are associated with severe IIH. Little is known about milder forms.

OBJECTIVE

This work aims to characterize the genetic associations and biochemical profile of mild IIH.

METHODS

This is a cross-sectional study including children between age 6 months and 17 years with IIH who were followed in the Calcium Clinic at the Hospital for Sick Children (SickKids), Toronto, Canada. Twenty children with mild IIH on calcium-restricted diets were evaluated. We performed a dietary assessment and analyzed biochemical measures including vitamin D metabolites and performed a stepwise molecular genetic analysis. Complementary biochemical assessments and renal ultrasounds were offered to first-degree family members of positive probands.

RESULTS

The median age was 16 months. Median serum levels of calcium (2.69 mmol/L), urinary calcium:creatinine ratio (0.72 mmol/mmol), and 1,25(OH)2D (209 pmol/L) were elevated, whereas intact PTH was low normal (22.5 ng/L). Mean 1,25(OH)2D/PTH and 1,25(OH)2D/25(OH)D ratios were increased by comparison to healthy controls. Eleven individuals (55%) had renal calcification. Genetic variants were common (65%), with the majority being heterozygous variants in SLC34A1 and SLC34A3, while a minority showed variants of CYP24A1 and other genes related to hypercalciuria.

CONCLUSION

The milder form of IIH has a distinctive vitamin D metabolite profile and is primarily associated with heterozygous SLC34A1 and SLC34A3 variants.