Arsenic Exposure in Well Water From the Perspective of Patients and Providers.

BACKGROUND: Arsenic is a well-known toxin which may contaminate household water. It is harmful when ingested over prolonged periods of time. As a result, public health experts recommend that water should be screened and treated to prevent arsenic ingestion. In the United States, the responsibility of testing and treatment of private wells falls on homeowners. Despite recommendations for routine screening, this is rarely done. OBJECTIVES: To assess the prevalence of well water use in a Midwestern patient population, how patients and clinicians perceive the risks of arsenic in well water, and whether additional resources on well water testing are desired. These findings will be used to influence tools for clinicians regarding symptom and examination findings of chronic arsenic exposure and potentiate the distribution of informational resources on well water testing. METHODS: Surveys were sent via email to all actively practicing primary care clinicians at the Mayo Clinic in the United States Midwest, and all active adult patients at the Mayo Clinic in the same region. Our team analyzed survey data to determine whether both patients and clinicians are aware of the health effects of chronic arsenic toxicity from well water, the need for routine well water testing and whether each group wants more information on the associated risks. RESULTS: Both patients and primary care clinicians worry about arsenic exposure. Patients with well water are concerned about their water safety yet feel uninformed about testing options. Clinicians do not know how prevalent well water use is among their patients, feel uninformed about the chronic risks of arsenic exposure and the physical examination associated with it. Both groups unanimously want more information on testing options. CONCLUSIONS: Our findings show a significant reliance on well water use in the American Midwest, and unanimous support for the need for further well water testing information and resources for patients and their clinicians.

Serum 25-hydroxyvitamin D threshold and risk of rickets in young children: a systematic review and individual participant data meta-analysis to inform the development of dietary requirements for vitamin D.

PURPOSE: The objective of this systematic review was to determine a minimum serum 25-hydroxyvitamin D (25OHD) threshold based on the risk of having rickets in young children. This work was commissioned by the WHO and FAO within the framework of the update of the vitamin D requirements for children 0-3 years old. METHODS: A systematic search of Embase was conducted to identify studies involving children below  4 years of age with serum 25OHD levels and radiologically confirmed rickets, without any restriction related to the geographical location or language. Study-level and individual participant data (IPD)-level random effects multi-level meta-analyses were conducted. The odds, sensitivity and specificity for rickets at different serum 25OHD thresholds were calculated for all children as well as for children with adequate calcium intakes only. RESULTS: A total of 120 studies with 5412 participants were included. At the study-level, children with rickets had a mean serum 25OHD of 23 nmol/L (95% CI 19-27). At the IPD level, children with rickets had a median and mean serum 25OHD of 23 and 29 nmol/L, respectively. More than half (55%) of the children with rickets had serum 25OHD below 25 nmol/L, 62% below 30 nmol/L, and 79% below 40 nmol/L. Analysis of odds, sensitivities and specificities for nutritional rickets at different serum 25OHD thresholds suggested a minimal risk threshold of around 28 nmol/L for children with adequate calcium intakes and 40 nmol/L for children with low calcium intakes. CONCLUSION: This systematic review and IPD meta-analysis suggests that from a public health perspective and to inform the development of dietary requirements for vitamin D, a minimum serum 25OHD threshold of around 28 nmol/L and above would represent a low risk of nutritional rickets for the majority of children with an adequate calcium intake.

Analysis of vitamin D3-sulfate and 25-hydroxyvitamin D3-sulfate in breastmilk by LC-MS/MS.

Sulfated metabolites of vitamin D have been suggested to be in breastmilk, although current methods to measure sulfated vitamin D compounds in breastmilk by liquid chromatography-tandem mass spectrometry (LC-MS/MS) have not adequately accounted for increased aqueous solubility of these sulfated metabolites. The purpose of this study was to generate a method of LC-MS/MS for measuring vitamin D3-3-sulfate (VitD3-S) and 25-hydroxyvitamin D3-3-sulfate (25OHD3-S) specifically in human breastmilk. The resulting method uses methanol to precipitate protein and solid phase extraction to prepare the samples for LC-MS/MS. The limits of quantification for analytes in solvent were 0.23 ng/mL VitD3-S and 0.2 ng/mL 25OHD3-S. Various experiments observed concentrations ranging 0.53 to 1.7 ng/mL VitD3-S and ≤ 0.29 ng/mL 25OHD3-S. Both analytes were present in aqueous skim milk, demonstrating the enhanced aqueous solubility of these vitamin D sulfates. In conclusion, we describe an effective method for measuring VitD3-S and 25OHD3-S in breastmilk by LC-MS/MS.

Disparities in Diabetes Care: Differences Between Rural and Urban Patients Within a Large Health System.

PURPOSE: We sought to ascertain factors associated with the quality of diabetes care, comparing rural vs urban diabetic patients in a large health care system. METHODS: We conducted a retrospective cohort study assessing patients' attainment of the D5 metric, a diabetes care metric having 5 components (no tobacco use, glycated hemoglobin [A1c] level less than 8%, blood pressure less than 140/90 mm Hg, low-density lipoprotein cholesterol level at goal or statin prescribed, and aspirin use consistent with clinical recommendations). Covariates included age, sex, race, adjusted clinical group (ACG) score as a marker of complexity, insurance type, primary care clinician type, and health care use data. RESULTS: The study cohort consisted of 45,279 patients with diabetes, 54.4% of whom resided in rural locations. The D5 composite metric was met in 39.9% of rural patients and 43.2% of urban patients (P <.001). Rural patients were significantly less likely to have attained all metric goals than urban counterparts (adjusted odds ratio [AOR] = 0.93; 95% CI, 0.88-0.97). The rural group had fewer outpatient visits (mean number of visits = 3.2 vs 3.9, P <.001) and less often had an endocrinology visit (5.5% vs 9.3%, P <.001) during the 1-year study period. Patients with an endocrinology visit were less likely to have met the D5 metric (AOR = 0.80; 95% CI, 0.73-0.86), whereas the more outpatient visits patients had, the greater their likelihood of attainment (AOR per visit = 1.03; 95% CI, 1.03-1.04). CONCLUSIONS: Rural patients had worse diabetes quality outcomes than their urban counterparts, even after adjustment for other contributing factors and despite being part of the same integrated health system. Lower visit frequency and less specialty involvement in the rural setting are possible contributing factors.

Vitamin D: immune function, inflammation, infections and auto-immunity.

Vitamin D plays an active role beyond mineral metabolism and skeletal health, including regulation of the immune system. Vitamin D deficiency is widely prevalent, and observational studies link low vitamin D status to a risk of infections and auto-immune disorders. Reports indicate an inverse relationship between vitamin D status and such conditions. This review details vitamin D signalling interactions with the immune system and provides experimental and clinical evidence evaluating vitamin D status, vitamin D supplementation and host susceptibility to infections, inflammation and auto-immunity. The published literature including related reviews, systematic reviews, meta-analyses, randomised controlled trials (RCTs), observational studies and basic science reports have been synthesised. Meta-analyses of observational studies have demonstrated a link between low vitamin D status and risk of acute respiratory infections, COVID-19 disorders, multiple sclerosis, type 1 diabetes (T1DM), inflammatory bowel disease (IBD), systemic lupus erythematosus and other auto-immune disorders. Observational studies suggest that vitamin D supplementation may protect against several infectious and auto-immune conditions. Meta-analyses of RCTs had mixed results, demonstrating a small protective role for vitamin D supplementation against acute respiratory infections, especially in those with vitamin D deficiency and children, and providing modest benefits for the management of T1DM and IBD. Vitamin D status is inversely associated with the incidence of several infectious and auto-immune conditions. Supplementation is recommended for those with vitamin D deficiency or at high risk of deficiency, and it might provide additional benefit in acute respiratory infections and certain auto-immune conditions.

Serum 1,25-dihydroxyvitamin D levels in the diagnosis and pathogenesis of nutritional rickets - a multivariable re-analysis of a case-control study.

BACKGROUND: A multivariable logistic regression model resulting from a case-control study of nutritional rickets in Nigerian children suggested that higher levels of serum 25(OH)D may be required to prevent nutritional rickets in populations with low-calcium intakes. OBJECTIVES: This current study evaluates if adding serum 1,25-dihydroxyvitamin D [1,25(OH)2D] to that model shows that increased levels of serum 1,25(OH)2D are independently associated with risk of children on low-calcium diets having nutritional rickets. METHODS: Multivariable logistic regression analysis was used to model the association between serum 1,25(OH)2D and risk of having nutritional rickets in cases (n = 108) and controls (n = 115) after adjusting for age, sex, weight-for age z-score, religion, phosphorus intake and age began walking and the interaction between serum 25(OH)D and dietary calcium intake (Full Model). RESULTS: Serum 1,25(OH)2D levels were significantly higher (320 pmol/L vs. 280 pmol/L) (P = 0.002), and 25(OH)D levels were lower (33 nmol/L vs. 52 nmol/L) (P < 0.0001) in children with rickets than in control children. Serum calcium levels were lower in children with rickets (1.9 mmol/L) than in control children (2.2 mmol/L) (P < 0.001). Dietary calcium intakes were similarly low in both groups (212 mg/d) (P = 0.973). In the multivariable logistic model, 1,25(OH)2D was independently associated with risk of having rickets [coefficient = 0.007 (95% confidence limits: 0.002-0.011)] after adjusting for all variables in the Full Model. CONCLUSIONS: Results confirmed theoretical models that in children with low dietary calcium intake, 1,25(OH)2D serum concentrations are higher in children with rickets than in children without rickets. The difference in 1,25(OH)2D levels is consistent with the hypothesis that children with rickets have lower serum calcium concentrations which prompt the elevation of PTH levels resulting in an elevation of 1,25(OH)2D levels. These results support the need for additional studies to identify dietary and environmental risks for nutritional rickets.

Highlights from the 24th workshop on vitamin D in Austin, September 2022.

The 24th Workshop on Vitamin D was held September 7-9, 2022 in Austin, Texas and covered a wide diversity of research in the vitamin D field from across the globe. Here, we summarize the meeting, individual sessions, awards and presentations given.

Infant and Maternal Vitamin D Supplementation: Clinician Perspectives and Practices.

INTRODUCTION: Rates of infant vitamin D supplementation fall short of guideline recommendations. We explored this discrepancy from the clinician perspective as they advise and affect this important intervention to prevent rickets. We compared infant and high-dose maternal vitamin D supplementation prescribing attitudes and practices between infant-only clinicians (IC) and clinicians who care for mothers and infants (MIC). METHODS: We surveyed clinicians in departments of family medicine, obstetrics/gynecology, primary care pediatrics, neonatology, newborn nursery, and members of vitamin D and rickets working groups and a social media group for lactation medicine providers about their perspectives and practices regarding vitamin D supplementation. RESULTS: 360 clinician survey responses were analyzed. In current practice, IC were more likely than MIC to recommend vitamin D supplementation to exclusively (P < .001) and partially breastfed infants (P = .005). MIC were more likely than IC to discuss infant and high-dose maternal supplementation options and let the parents/caregivers choose (34.7%, 22.0%, P = .009). If supplementing the mother with high-dose vitamin D or the infant directly each provided adequate vitamin D in the infant, MIC were more likely than IC to think that supplementation of the mother would be preferred by parents/caregivers (63.0%, 45.2%, P = .003), improve adherence (66.5%, 49.4%, P = .006), and promote breastfeeding (54.7%, 36.5%, P = .001); they were also more likely to recommend supplementation of the mother (17.7%, 8.9%, P = .04). CONCLUSIONS: MIC are more likely than IC to embrace high-dose maternal vitamin D supplementation to provide adequate vitamin D for infants. This highlights an opportunity for further education of clinicians about this option.

Clinician Adoption of an Artificial Intelligence Algorithm to Detect Left Ventricular Systolic Dysfunction in Primary Care.

OBJECTIVE: To compare the clinicians' characteristics of "high adopters" and "low adopters" of an artificial intelligence (AI)-enabled electrocardiogram (ECG) algorithm that alerted for possible low left ventricular ejection fraction (EF) and the subsequent effectiveness of detecting patients with low EF. METHODS: Clinicians in 48 practice sites of a US Midwest health system were cluster-randomized by the care team to usual care or to receive a notification that suggested ordering an echocardiogram in patients flagged as potentially having low EF based on an AI-ECG algorithm. Enrollment was between June 26, 2019, and July 30, 2019; participation concluded on March 31, 2020. This report is focused on those clinicians randomized to receive the notification of the AI-ECG algorithm. At the patient level, data were analyzed for the proportion of patients with positive AI-ECG results. Adoption was defined as the clinician order of an echocardiogram after prompted by the alert. RESULTS: A total of 165 clinicians and 11,573 patients were included in this analysis. Among patients with positive AI-ECG, high adopters (n=41) were twice as likely to diagnose patients with low EF (33.9%) vs low adopters, n=124, (16.9%); odds ratio, 1.62; 95% CI, 1.21 to 2.17). High adopters were more often advanced practice providers (eg, nurse practitioners and physician assistants) vs physicians, Family Medicine vs Internal Medicine specialty, and tended to have less complex patients. CONCLUSION: Clinicians who most frequently followed the recommendations of an AI tool were twice as likely to diagnose low EF. Those clinicians with less complex patients were more likely to be high adopters. TRIAL REGISTRATION: Clinicaltrials.gov Identifier: NCT04000087.

Evaluating the Evidence in Clinical Studies of Vitamin D in COVID-19.

Laboratory evidence provides a biological rationale for the benefits of vitamin D in COVID-19, and vitamin D supplementation is associated with reduced risk of respiratory infections. Most of the clinical studies of vitamin D in COVID-19 have been observational, and the most serious problem with observational study design is that of confounding. Observational studies typically assess the relationship of 25(OH)D values with COVID-19 outcomes. Many conditions associated with low vitamin D status are also associated with worse COVID-19 outcomes. Randomized controlled trials (RCTs) overcome the problem of confounding, typically comparing outcomes between groups receiving vitamin D supplementation or placebo. However, any benefit of vitamin D in COVID-19 may be related to the dose, duration, daily vs. bolus administration, interaction with other treatments, and timing of administration prior to or during the illness. Serum 25(OH)D values >50 nmol/L have been associated with reduced infection rates, severity of COVID-19, and mortality in observational studies. Few RCTs of vitamin D supplementation have been completed, and they have shown no benefit of vitamin D in hospitalized patients. Vitamin D may benefit those with mild or asymptomatic COVID-19, and those with greater 25(OH)D values may have lower risk of acquiring infection. Because those at greatest risk of COVID-19 are also at greatest risk of vitamin D deficiency, it is reasonable to recommend vitamin D supplementation 15−20 mcg (600−800 IU) daily for the general population during the COVID-19 pandemic. Vitamin D doses greater than 100 mcg (4000 IU) daily should not be used without monitoring serum 25(OH)D and calcium.

Association of Perinatal Factors With Severe Obesity and Dyslipidemia in Adulthood.

BACKGROUND: Perinatal factors including gestational age, birthweight, size for gestational age, delivery route, maternal parity, maternal age, maternal education, socioeconomic status, race, and sex, are associated with the future risk of obesity and co-morbid conditions. This study evaluated the relationship of birthweight for gestational age and perinatal factors with severe obesity and dyslipidemia in adulthood. METHODS: We conducted a population-based, retrospective birth cohort study of infants born to residents of Olmsted County, MN between 1976 and 1982. Outcomes were assessed after age 18 years until October 2020, including severe obesity (BMI ≥ 40 kg/m2) and dyslipidemia (total cholesterol ≥200 mg/dL, non-high density lipoprotein [non-HDL] cholesterol ≥145 mg/dL or HDL cholesterol <40 mg/dL). We obtained mother's age, education level, and parity as well as newborn sex, race, type of delivery, single/multiple birth, gestational age, and birthweight from birth certificate data. Individual-level socioeconomic status (SES) of the household at birth was determined with the HOUSES index. RESULTS: Of 10 938 birth cohort subjects, 7394 had clinic visits after age 18 years and were included, with 2630 having severe obesity (n = 798) or dyslipidemia (n = 2357) as adults. In multivariable models, female sex, singleton birth, less maternal education, and lower SES defined by HOUSES were independently associated with an increased risk of severe obesity in adulthood. Non-white race, singleton birth, and lower birthweight were independently associated with adult dyslipidemia. Birthweight for gestational age was not associated with severe obesity or dyslipidemia. CONCLUSION: Perinatal factors were associated with both severe obesity and dyslipidemia in adulthood. Lower SES at birth was predictive of severe obesity in adulthood, highlighting the opportunity to investigate modifiable perinatal social determinants to reduce the risk of severe obesity.

Vitamin D Status and Severe COVID-19 Disease Outcomes in Hospitalized Patients.

BACKGROUND: Vitamin D deficiency may increase the risk of severe COVID-19 disease. OBJECTIVES: To determine if 25-hydroxyvitamin D [25(OH)D] levels in patients hospitalized for COVID-19 were associated with the clinical outcomes of days on oxygen, duration of hospitalization, ICU admission, need for assisted ventilation, or mortality. METHODS: We conducted a retrospective study of 92 patients admitted to the hospital with SARS-CoV-2 infection between April 16, 2020 and October 17, 2020. Multivariable regression was performed to assess the independent relationship of 25(OH)D values on outcomes, adjusting for significant covariates and the hospitalization day the level was tested. RESULTS: About 15 patients (16.3%) had 25(OH)D levels <20 ng/mL. Only 1 patient (3.4%) who had documented vitamin D supplementation prior to admission had 25(OH)D <20 ng/mL. Serum 25(OH)D concentrations were not significantly associated with any of our primary outcomes of days on oxygen, duration of hospitalization, intensive care unit (ICU) admission, need for mechanical ventilation, or mortality in any of the adjusted multivariable models. Adjusting for the hospital day of 25(OH)D sampling did not alter the relationship of 25(OH)D with any outcomes. CONCLUSION: Vitamin D status was not related to any of the primary outcomes reflecting severity of COVID-19 in hospitalized patients. However, our sample size may have lacked sufficient power to demonstrate a small effect of vitamin D status on these outcomes.

Serum 25-Hydroxyvitamin D and Subsequent Cancer Incidence and Mortality: A Population-Based Retrospective Cohort Study.

OBJECTIVE: To determine the relationship between 25-hydroxyvitamin D (25[OH]D) values and subsequent cancer incidence and mortality. PATIENTS AND METHODS: We identified all adult patients living in Olmsted County, Minnesota, between January 1, 2005, and December 31, 2011, who had at least 1 25(OH)D measurement and no prior diagnosis of cancer. Cancer outcomes were retrieved starting 30 days after 25(OH)D measurement and until patients' final clinical visit as an Olmsted County resident; December 31, 2014; or death. Cox proportional hazards regression was used to analyze data. RESULTS: A total of 8700 individuals had a 25(OH)D measurement and no history of cancer, with a mean ± SD 25(OH)D value of 29.7±12.8 ng/mL (to convert to nmol/L, multiply by 2.496). The mean ± SD age was 51.5±16.4 years, and most were women (78.1%; n=6796) and White (85.7%; n=7460). A total of 761 individuals developed cancer (skin cancer, n=360; nonskin cancer, n=401) during a median follow-up of 4.6 (interquartile range, 3.4-6.1) years. Compared with participants with 25(OH)D values of 20 to 50 ng/mL (reference group), those with 25(OH)D values less than 12 ng/mL had a greater nonskin cancer incidence (hazard ratio [HR], 1.56; 95% CI, 1.03 to 2.36; P=.04) after adjustment. There was no association between 25(OH)D values and total cancer or skin cancer incidence. Compared with individuals from the reference group, 25(OH)D levels less than 12 ng/mL (HR, 2.35; 95% CI, 1.01 to 5.48; P=.047) and 12 to 19 ng/mL (HR, 2.10; 95% CI, 1.05 to 4.22; P=.04) were associated with increased cancer mortality. CONCLUSION: Low 25(OH)D levels were associated with increased risk for incident nonskin cancer and cancer-related mortality.

Serum 25-hydroxyvitamin D values and risk of incident cardiovascular disease: A population-based retrospective cohort study.

BACKGROUND: Concentrations of serum 25-hydroxyvitamin D [25(OH)D] below 20 ng/mL and above 50 ng/mL have been associated with chronic adverse events including cardiovascular disease. OBJECTIVE: To conduct a comprehensive population-based study in the United States of the relationship of low and high serum 25(OH)D levels with cardiovascular disease. METHODS: We identified all serum 25(OH)D measurements in adults age 18 years and older residing in Olmsted County, MN between January 1, 2005 and December 31, 2011, using the resources of the Rochester Epidemiology Project. Any new diagnosis of cardiovascular disease was the primary outcome, and time zero was 30 days after first 25(OH)D measurement. Patients were followed until their last clinical visit as an Olmsted County resident, December 31, 2014, or death. Categories of 25(OH)D values were examined using predetermined ranges of interest: <12, 12-19, 20-50 (reference range), and >50 ng/mL. Multivariable Cox proportional hazards models were adjusted for age, BMI, sex, race, smoking history, season of 25(OH)D measurement, hypertension, hyperlipidemia, socioeconomic status and Charlson comorbidity index at time of 25(OH)D measurement. RESULTS: A total of 11,002 unique persons had a 25(OH)D measurement, with a mean (±SD) value of 30.0 ± 12.9 ng/mL. Mean age was 54.3 ± 17.2 years, and the majority were female (77.1 %) and white (87.6 %). There were 4124 new diagnoses of cardiovascular disease in this cohort after a median overall follow-up of 4.8 years (IQR 3.4-6.2). Adjusted cardiovascular disease hazard ratios (HRs) (95 % confidence interval) for 25(OH)D values <12, 12-19, and >50 ng/mL, compared to the reference range 20-50 ng/mL, were 1.28 (1.12-1.46), 1.19 (1.09-1.31), and 1.10 (0.95-1.26), respectively. CONCLUSION: Values of 25(OH)D <20 ng/mL were associated with development of a new diagnosis of cardiovascular disease. There was no significant association between 25(OH)D values >50 ng/mL and cardiovascular disease.

Clinician Care Team Composition and Health Care Utilization.

OBJECTIVE: To test the hypothesis that a greater proportion of physician time on primary care teams are associated with decreased emergency department (ED) visits, hospital admissions, and readmissions, and to determine clinician and care team characteristics associated with greater utilization. PATIENTS AND METHODS: We retrospectively analyzed administrative data collected from January 1 to December 31, 2017, of 420 family medicine clinicians (253 physicians, 167 nurse practitioners/physician assistants [NP/PAs]) with patient panels in an integrated health system in 59 Midwestern communities serving rural and urban areas in Minnesota, Wisconsin, and Iowa. These clinicians cared for 419,581 patients through 110 care teams, with varying numbers of physicians and NP/PAs. Primary outcome measures were rates of ED visits, hospitalizations, and readmissions. RESULTS: The proportion of physician full-time equivalents on the team was unrelated to rates of ED visits (rate ratio [RR] = 0.826; 95% confidence interval [CI], 0.624 to 1.063), hospitalizations (RR = 0.894; 95% CI, 0.746 to 1.072), or readmissions (RR = -0.026; 95% CI, 0.364 to 0.312). In separate multivariable models adjusted for clinician and practice-level characteristics, the rate of ED visits was positively associated with mean panel hierarchical condition category (HCC) score, urban vs rural setting, NP/PA vs physician, and lower years in practice. The rate of inpatient admissions was associated with HCC score, and 30-day hospital readmissions were positively associated with HCC score, lower years in practice, and male clinicians. CONCLUSION: Care team physician and NP/PA composition was not independently related to utilization. More complex panels had higher rates of ED visits, hospitalization, and readmissions. Statistically significant differences between physician and NP/PA panels were only evident for ED visits.

The Validity of Serum Alkaline Phosphatase to Identify Nutritional Rickets in Nigerian Children on a Calcium-Deprived Diet.

CONTEXT: Nutritional rickets results from the interaction of low vitamin D status and limited calcium intake. Serum alkaline phosphatase (AP) activity is a biomarker of impaired mineralization in rickets. OBJECTIVE: To assess the performance of serum AP activity in identifying nutritional rickets in calcium-deprived Nigerian children. METHODS: We reanalyzed data from a case-control study of children with active rickets and matched control subjects without rickets, using a multivariate logistic regression to assess the odds of rickets associated with AP activity, adjusting for age, sex, and weight-for-age z-score. RESULTS: A total of 122 children with rickets and 119 controls were included. Rachitic children had a mean (±SD) age of 54 ±â€…29 months, and 55 (45.1%) were male. Cases and controls had low dietary calcium intakes (216 ±â€…87 and 214 ±â€…96 mg/day, respectively). Serum AP activity levels in cases and controls were 812 ±â€…415 and 245 ±â€…78 U/L, respectively (P < 0.001). AP was negatively associated with 25-hydroxyvitamin D values (r = -0.34; P < 0.001). In the adjusted model, the odds ratio (95% CI) receiver operating characteristic curve was 0.978. AP > 350 U/L identified nutritional rickets in Nigerian children with sensitivity 0.93, specificity 0.92, positive likelihood ratio 11.3, and negative likelihood ratio 0.07. CONCLUSION: An AP > 350 U/L effectively discriminated between Nigerian children with and without nutritional rickets. AP is a low-cost biochemical test that could be used to screen for nutritional rickets, but cutoff values require validation in other populations, and laboratory values need to be standardized for widespread population studies.

Validation of the Radiographic Global Impression of Change (RGI-C) score to assess healing of rickets in pediatric X-linked hypophosphatemia (XLH).

BACKGROUND: Rickets is a primary manifestation of pediatric X-linked hypophosphatemia (XLH) - a rare progressive hereditary phosphate-wasting disease. Severity is quantified from radiographs using the Rickets Severity Scale (RSS). The Radiographic Global Impression of Change (RGI-C) is a complementary assessment in which a change score is assigned based on differences in the appearance of rickets on pairs of radiographs compared side by side. OBJECTIVE: The current study evaluated the reliability, validity, and sensitivity to change of the RGI-C specifically in pediatric XLH. METHODS: The reliability, validity, and sensitivity to change of the RGI-C were evaluated using data from two studies in pediatric XLH (113 children aged 1-12 years) in which burosumab treatment significantly improved rickets severity. Intra-rater and inter-rater reliability were assessed by three pediatric radiologists. RESULTS: Intra-rater reliability for RGI-C global score was >90% for agreement within 1 point, with weighted kappa values >0.5, indicating moderate to almost perfect agreement. Inter-rater reliability was also >90% (0.47-0.52 for all reader pairs; moderate agreement). The RGI-C global score showed significant relationships with changes from baseline to week 64 in serum phosphorus (r = -0.397), alkaline phosphatase (-0.611), total RSS (-0.672), standing height (0.268), and patient-reported global functioning (0.306) and comfort/pain functioning (0.409). Based on standardized response means, RGI-C global scores were sensitive to change in RSS, differentiating between those considered improved and greatly improved. Results for validity and sensitivity to change were similar for the RGI-C wrist, knee, and standing long leg scores. CONCLUSION: The RGI-C is a reliable, valid, and sensitive measure in pediatric XLH, and complementary to the RSS.