Daily Endocrinology Research Analysis

INTRODUCTION: Race-specific reference ranges for pediatric areal bone mineral density (BMD) are widely used, but the value of race-based clinical algorithms has been questioned. We developed race-neutral pediatric reference ranges for areal BMD and bone mineral apparent density (BMAD) and compared race-specific vs race-neutral Z-scores in their ability to predict prospective fractures.

MATERIAL AND METHODS: This secondary analysis of the Bone Mineral Density in Childhood Study used longitudinal BMD data of the spine, hip, forearm, and total body less head and BMAD from dual-energy x-ray absorptiometry (DXA) scans. Race/ethnicity, dietary calcium, physical activity, and prospective fractures were assessed by questionnaire. Race-neutral reference ranges and height-for-age Z-score adjustment equations were created using the lambda-sigma-mu method. Race-neutral and race-specific Z-scores were compared using linear mixed-effect modeling. Cox proportional hazard modeling was used to test whether race-neutral Z-scores associated with fracture.

RESULTS: Race-neutral BMD and BMAD Z-scores were 0.5 to 0.7 SD greater than race-specific Z-scores for Black children but only ∼0.1 SD lower for children from other race/ethnicity groups. Growth and lifestyle factors modified group differences. One SD increase in race-neutral Z-scores was associated with a 12% to 18% reduced risk of fracture.

CONCLUSION: We present the first race-neutral pediatric reference ranges for BMD and BMAD that are weighted to be representative of the US population and demonstrate that these Z-scores associate with fracture risk. Adoption of these new reference ranges should be considered, with thoughtful implementation for patients previously monitored with race-specific reference ranges, especially among children who identify as Black.

BACKGROUND: The burden of obesity-related health conditions remains incompletely explored. Previous studies have been underpowered to study severe obesity, focused on a limited set of health outcomes, and lacked diversity in study populations. METHODS: We studied 270,657 participants from the All of Us research program with linked electronic health records and body mass index (the weight in kilograms divided by the square of the height in meters) greater than or equal to 18.5. We investigated the prevalence and incidence of 16 a priori-identified outcomes covering cardiovascular-kidney-metabolic syndrome and others: hypertension, type 2 diabetes mellitus, hyperlipidemia/dyslipidemia, heart failure, atrial fibrillation, atherosclerotic cardiovascular disease, chronic kidney disease, pulmonary embolism, deep vein thrombosis, gout, metabolic dysfunction-associated steatotic liver disease, biliary calculus, obstructive sleep apnea, asthma, gastroesophageal reflux disease, and osteoarthritis. Adjusted hazard ratios were calculated for each BMI category and compared with normal weight. The population-attributable fraction was calculated for different obesity classifications. RESULTS: The included population was 62.0% women and 22.0% Black. Class I, II, and III obesity was observed in 21.2%, 11.3%, and 9.8% of participants, respectively. Obesity was strongly associated with all incident outcomes, with graded associations across higher classes of obesity. Class III obesity was most strongly associated with obstructive sleep apnea, type 2 diabetes mellitus, and metabolic dysfunction-associated steatotic liver disease (hazard ratio [95% confidence interval {CI}], 10.94 [9.97 to 12.00], 7.74 [7.03 to 8.53], and 6.72 [6.01 to 7.50], respectively), with weaker associations for asthma, osteoarthritis, and atherosclerotic cardiovascular disease (hazard ratio [95% CI], 2.14 [1.95 to 2.35], 2.06 [1.94 to 2.19], and 1.96 [1.70 to 2.25], respectively). Associations were consistent across sex and race. The obesity-related population-attributed fraction ranged from 14.0% (osteoarthritis) to 51.5% (obstructive sleep apnea) in this population. CONCLUSIONS: Obesity, particularly severe obesity, was strongly associated with the incidence of 16 common health outcomes.

CONTEXT: Hereditary medullary thyroid carcinoma (MTC) is an inherited syndrome accounting for 25% of MTC cases. It is caused by germline RET mutations, which can be inherited or occur de novo. OBJECTIVE: This study aimed to define the prevalence and genetics of de novo MEN2 syndromes, which are not yet fully understood, and to characterize the parental origin of the RET de novo mutation. METHODS: We selected 152 of 215 families with hereditary MTC. In de novo cases, we sequenced the wild-type and mutated alleles of the index cases and compared their single nucleotide polymorphism profiles with those of their parents. Digital droplet PCR was performed to determine the presence of mosaicism in both the index case and the parents. RESULTS: In 24 of 152 (15.78%) families, the index case had a de novo mutation. Single nucleotide polymorphism analysis demonstrated that in all cases, the mutation occurred on the paternal allele. The absence of mosaicism supported the hypothesis that the mutation occurred during spermatogenesis. The mean age of fathers at the time of conception was, in some cases but not all, relatively advanced. CONCLUSION: The prevalence of de novo hereditary MEN2 syndromes was approximately 16%, including MEN2B, and around 9% for other phenotypes. All de novo cases were of paternal origin and likely resulted from an acquired alteration in sperm DNA. The possible role of advanced paternal age in promoting de novo mutations could not be ruled out.