Calcium and vitamin D requirements for optimal bone mass during adolescence

Nutrient Deficiency After Bariatric Surgery in Adolescents: A Systematic Review and Meta-Analysis

OBJECTIVE

This systematic review and meta-analysis study aimed to estimate changes in blood nutrient concentrations and nutrient deficiencies in adolescents following bariatric surgery.

METHODS

We searched PubMed, Scopus, and the Web of Science to find studies published between January 2000 and August 2023. Observational studies reporting the mean blood concentration of nutrients before and after bariatric surgery or the proportion of nutrient deficiencies after the surgery in healthy adolescents were selected.

RESULTS

Fifteen studies were included. Gastric bypass and sleeve gastrostomy were the most common types of surgery. Vitamin D, iron, or ferritin, vitamin B12, calcium, and folic acid were the most studied nutrients, respectively. Other nutrients examined in the studies included zinc, phosphorus, and albumin. The serum ferritin increased by 21 mcg/L (95% CI = 10.0, 32.0 mcg/L) after the surgery, but there were no significant alterations in other nutrients. The postoperative prevalence of low albumin, ferritin, vitamin D, and vitamin B12 levels was 10%, 49%, 41%, and 20%, respectively. Also, 23% had an iron deficiency, and 10% had a calcium deficiency after bariatric surgery.

CONCLUSIONS

The serum ferritin level increased following bariatric surgery in adolescents. Vitamin D and ferritin deficiencies were estimated to be present in more than one-third of adolescents after the surgery.

Bone Health in School Age Children: Effects of Nutritional Intake on Outcomes

The maximum rate of bone mass accumulation is during early adolescence. As such, a focus on optimizing mineral nutrition in school age children, defined here as approximately 5 to 15 years of age, is crucial to minimize the risk of bone loss that occurs later in life leading to osteoporosis and fractures. Optimizing bone mass in this age group requires attention to an overall healthy diet including adequate calcium, phosphorus, magnesium, and vitamin D. Special concerns may exist related to children who follow a restricted diet such as a vegan diet, those with intolerance or allergies to dairy, and those with chronic health conditions including young adolescents with eating disorders. Public policy messages should focus on positive aspects of bone health nutrition in this age group and avoid overly specific statements about the exact amounts of foods needed for healthy bones. In this regard, dietary recommendations for minerals vary between North America and Europe and these are higher than the values that may be necessary in other parts of the world. The management of many children with chronic illnesses includes the use of medications that may affect their bone mineral metabolism. Routine lab testing for bone mineral metabolism including the serum 25-hydroxyvitamin D level is not indicated, but is valuable for at-risk children, especially those with chronic illnesses.

Dairy- and supplement-based calcium intake in adulthood and vertebral dimensions in midlife-the Northern Finland Birth Cohort 1966 Study

Among a representative sample of 1064 Northern Finns, we studied the association of dairy- and supplement-based calcium intake in adulthood with vertebral size in midlife. Inadequate calcium intake (< 800 mg/day) from age 31 to 46 predicted small vertebral size and thus decreased spinal resilience among women but not men.

INTRODUCTION

Small vertebral size predisposes individuals to fractures, which are common among aging populations. Although previous studies have associated calcium (Ca) intake with enhanced bone geometry in the appendicular skeleton, few reports have addressed the axial skeleton or the vertebrae in particular. We aimed to investigate the association of dairy- and supplement-based Ca intake in adulthood with vertebral cross-sectional area (CSA) in midlife.

METHODS

A sample of 1064 individuals from the Northern Finland Birth Cohort 1966 had undergone lumbar magnetic resonance imaging at the age of 46, and provided self-reported data on diet and Ca intake (dairy consumption and use of Ca supplements) at the ages of 31 and 46. We assessed the association between Ca intake (both continuous and categorized according to local recommended daily intake) and vertebral CSA, using generalized estimating equation and linear regression models with adjustments for body mass index, diet, vitamin D intake, education, leisure-time physical activity, and smoking.

RESULTS

Women with inadequate Ca intake (< 800 mg/day) over the follow-up had 3.8% smaller midlife vertebral CSA than women with adequate Ca intake (p = 0.009). Ca intake among men showed no association with vertebral CSA.

CONCLUSIONS

Inadequate Ca intake (< 800 mg/day) from the age of 31 to 46 predicts small vertebral size and thus decreased spinal resilience among middle-aged women. Future studies should confirm these findings and investigate the factors underlying the association of low Ca intake in women but not in men with smaller vertebral size.

Dietary sources of calcium among parents and their early adolescent children in the United States by parent race/ethnicity and place of birth

Dietary calcium sources may differ by race/ethnicity and dietary acculturation. A cross-sectional, convenience sample including 587 United States (US) Asian, Hispanic and non-Hispanic White parent-child (10-13 years) pairs completed a calcium food frequency questionnaire. Calcium sources were ranked by mean percent contribution to total adjusted calcium intake, and compared by ethnic group and parents' location of birth. Five foods (fluid milk, cheese, milk on cereal, yogurt, and lattes) represented 49% of total calcium intake for parents. The same foods (except lattes) represented 55% of total calcium for early adolescent children. Fluid milk provided the largest mean percentage of intake for all race/ethnic groups among parents and children. Several food sources of calcium were greater for foreign-born versus US-born Asian or Hispanic parents and children. Understanding calcium food sources and changes in dietary patterns that affect calcium intake among parents and children is important to better promote adequate intake.

Perceptions of how parents of early adolescents will personally benefit from calcium-rich food and beverage parenting practices

OBJECTIVE

To identify and rank perceived personal benefits from parenting practices that promote intake of calcium-rich foods and beverages (CRF/B) by early adolescents.

METHODS

A convenience sample of parents/caregivers (n = 133) of early adolescents (10-13 years) from 6 states (CA, HI, MN, OH, OR, UT) participated in a qualitative study using a Nominal Group Technique process. Benefits identified by parents/caregivers were ranked by importance, given a score weight, and summed to create a total weighted score across states.

RESULTS

The top benefit from making CRF/B available was parent emotional rewards. The top benefit perceived by parents from role modeling intake of CRF/B and setting expectations for intake of CRB was child health promotion.

CONCLUSIONS AND IMPLICATIONS

Child health promotion and parent emotional rewards were important perceived benefits derived from CRF/B parenting practices, and thus, should be included as the focus of education to increase the frequency of these practices.

Effect of vitamin D replacement on hip structural geometry in adolescents: a randomized controlled trial

BACKGROUND

We have shown in a randomized controlled trial that vitamin D increases bone mass, lean mass and bone area in adolescent girls, but not boys. These increments may translate into improvements in bone geometry and therefore bone strength. This study investigated the impact of vitamin D on hip geometric dimensions from DXA-derived hip structural analyses in adolescents who participated in the trial.

METHODS

167 girls (mean age 13.1 years) and 171 boys (mean age 12.7 years) were randomly assigned to receive weekly placebo oil or vitamin D3, at doses of 1400 IU or 14,000 IU, in a double blind placebo-controlled 1-year trial. DXA images were obtained at baseline and one year, and hip images were analyzed using the hip structural analysis (HSA) software to derive parameters of bone geometry. These include outer diameter (OD), cross sectional area (CSA), section modulus (Z), and buckling ratio (BR) at the narrow neck (NN), intertrochanteric (IT), and shaft (S) regions. Analysis of Covariance (ANCOVA) was used to examine group differences for changes of bone structural parameters.

RESULTS

In the overall group of girls, vitamin D supplementation increased aBMD (7.9% and 6.8% in low and high doses, versus 4.2% in placebo) and reduced the BR of NN (6.1% and 2.4% in low and high doses, versus 1.9% in placebo). It also improved aBMD (7.9% and 5.2% versus 3.6%) and CSA (7.5% and 5.1% versus 4.1%) of the IT and OD of the S (2.4% and 2.5% versus 0.8% respectively). Significant changes in the OD and BR of the NN, in the overall group of girls remained, after adjusting for lean mass, and were unaffected with further adjustments for lifestyle, pubertal status, and height measures. Conversely, boys did not exhibit any significant changes in any parameters of interest. A dose effect was not detected and subgroup analyses revealed no beneficial effect of vitamin D by pubertal stage.

CONCLUSIONS

Vitamin D supplementation improved bone mass and several DXA-derived structural bone parameters, in adolescent girls, but not boys. This occurred at a critical site, the femoral neck, and if maintained through adulthood could improve bone strength and lower the risk of hip fractures.

Bone health in children and adolescents with perinatal HIV infection

The long-term impact on bone health of lifelong HIV infection and prolonged ART in growing and developing children is not yet known. Measures of bone health in youth must be interpreted in the context of expected developmental and physiologic changes in bone mass, size, density and strength that occur from fetal through adult life. Low bone mineral density (BMD) appears to be common in perinatally HIV-infected youth, especially outside of high-income settings, but data are limited and interpretation complicated by the need for better pediatric norms. The potential negative effects of tenofovir on BMD and bone mass accrual are of particular concern as this drug may be used more widely in younger children. Emphasizing good nutrition, calcium and vitamin D sufficiency, weight-bearing exercise and avoidance of alcohol and smoking are effective and available approaches to maintain and improve bone health in all settings. More data are needed to inform therapies and monitoring for HIV-infected youth with proven bone fragility. While very limited data suggest lack of marked increase in fracture risk for youth with perinatal HIV infection, the looming concern for these children is that they may fail to attain their expected peak bone mass in early adulthood which could increase their risk for fractures and osteoporosis later in adulthood.