The relationship of 25-hydroxyvitamin D concentrations and individual-level socioeconomic status

Evolution, the Immune System, and the Health Consequences of Socioeconomic Inequality

Healthy development and function of essentially all physiological systems and organs, including the brain, require exposure to the microbiota of our mothers and of the natural environment, especially in early life. We also know that some infections, if we survive them, modulate the immune system in relevant ways. If we study the evolution of the immune and metabolic systems, we can understand how these requirements developed and the nature of the organisms that we need to encounter. We can then begin to identify the mechanisms of the beneficial effects of these exposures. Against this evolutionary background, we can analyze the ways in which the modern urban lifestyle, particularly for individuals experiencing low socioeconomic status (SES), results in deficient or distorted microbial exposures and microbiomes. Thus, an evolutionary approach facilitates the identification of practical solutions to the growing scandal of health disparities linked to inequality.

Influence of maternal socioeconomic deprivation and living environment on newborn bloodspot 25-hydroxyvitamin D levels

Objectives

Vitamin D deficiency in neonates can have life-threatening consequences, hence the knowledge of risk factors is essential. This study aimed to explore the effect of maternal socioeconomic status (SES) on newborn 25-hydroxyvitamin D (25OHD) concentrations.

Design

Over two 1-week periods (winter and summer of 2019), 3000 newborn heel prick dried blood spots (DBS) and additional data of newborns, from a regional newborn screening laboratory (52° N) in the West Midlands, UK, were gathered. Post code was replaced with lower layer super output area (LSOA). Index of Multiple Deprivation (IMD) quintiles for the corresponding LSOA was used to assess SES [quintile one (Q1): most deprived 20%, quintile five (Q5): least deprived 20%]. Each of the seven domains of deprivation were examined (income, employment, education, health, barriers to housing and services, crime and living environment). 25OHD was measured on 6mm sub-punch from DBS using quantitative liquid chromatography tandem mass spectrometry and equivalent plasma values were derived.

Results

In total 2999 (1500 summer-born, 1499 winter-born) newborn DBS (1580 males) were analysed. Summer-born newborns had significantly higher 25OHD (IQR) concentrations [49.2 (34.3; 64.8) nmol/l] than winter-born newborns [29.1 (19.8; 40.6) nmol/l, p<0.001].25OHD levels varied significantly between the different IMD quintiles in the whole (p<0.001) and summer-born cohort (p<0.001), but not in the winter-born cohort (p=0.26), whereby Q1 had the lowest 25OHD concentrations. Among the domains of deprivation, living environment had a significant influence on 25OHD levels (β=0.07, p=0.002). In this subdomain, 25OHD levels varied significantly between quintiles in the whole (p<0.001) and summer-born cohort (mean 25OHD Q1 46.45 nmol/l, Q5 54.54 nmol/l; p<0.001) but not in the winter-born cohort (mean 25OHD Q1 31.57 nmol/l, Q5 31.72 nmol/l; p=0.16). In a regression model, living environment was still significant (p=0.018), albeit less than season of birth and ethnicity.

Conclusion

Among the seven domains of deprivation, maternal living environment had the greatest effect on newborn 25OHD levels. Whilst improved living environment positively influenced vitamin D status in the summer-born babies, winter-born had low 25OHD levels irrespective of the environment. Strategies such as enhanced supplementation and food fortification with vitamin D should be considered to overcome the non-modifiable main risk factors for vitamin D deficiency.

Role of geographic risk factors and social determinants of health in COVID-19 epidemiology: Longitudinal geospatial analysis in a midwest rural region

Background

Studies examining the role of geographic factors in coronavirus disease-2019 (COVID-19) epidemiology among rural populations are lacking.

Methods

Our study is a population-based longitudinal study based on rural residents in four southeast Minnesota counties from March through October 2020. We used a kernel density estimation approach to identify hotspots for COVID-19 cases. Temporal trends of cases and testing were examined by generating a series of hotspot maps during the study period. Household/individual-level socioeconomic status (SES) was measured using the HOUSES index and examined for association between identified hotspots and SES.

Results

During the study period, 24,243 of 90,975 residents (26.6%) were tested for COVID-19 at least once; 1498 (6.2%) of these tested positive. Compared to other rural residents, hotspot residents were overall younger (median age: 40.5 vs 43.2), more likely to be minorities (10.7% vs 9.7%), and of higher SES (lowest HOUSES [SES] quadrant: 14.6% vs 18.7%). Hotspots accounted for 30.1% of cases (14.5% of population) for rural cities and 60.8% of cases (27.1% of population) for townships. Lower SES and minority households were primarily affected early in the pandemic and higher SES and non-minority households affected later.

Conclusion

In rural areas of these four counties in Minnesota, geographic factors (hotspots) play a significant role in the overall burden of COVID-19 with associated racial/ethnic and SES disparities, of which pattern differed by the timing of the pandemic (earlier in pandemic vs later). The study results could more precisely guide community outreach efforts (e.g., public health education, testing/tracing, and vaccine roll out) to those residing in hotspots.

Stable Rates of Low Vitamin D Status Among Children Despite Increased Testing: A Population-Based Study

OBJECTIVE

To determine the trends in testing and incidence of vitamin D deficiency/insufficiency in Olmsted County, Minnesota over a 16-year period.

STUDY DESIGN

The Rochester Epidemiology Project (REP) was used to identify Olmsted County, Minnesota residents aged <19 years who had 25-hydroxyvitamin D [25(OH)D] levels measured between January 2, 2002 and December 31, 2017. Using each patient's first 25(OH)D measurement during this period, patients were categorized into 3 groups: <20 ng/mL, 20-50 ng/mL, and >50 ng/mL. Vitamin D deficiency/insufficiency was defined as a total 25(OH)D level of <20 ng/mL.

RESULTS

There was a 42-fold increase in the proportion of the county's pediatric population tested each year, starting at 3.7 per 10 000 persons in 2002 and increasing to 156.1 per 10 000 persons in 2017. The largest increase in testing occurred in children aged ≥10 years, specifically the females in this age group, in whom we observed a 90-fold increase from 2002 to 2017. During the 16-year period, the incidence of vitamin D deficiency/insufficiency (per 10 000 persons) increased from 1.7 in 2002-2003 to 19.9 in 2016-2017, but the proportion that were tested and had vitamin D deficiency/insufficiency remained stable, with rates of 21.9% (95% CI, 16.1%-29.1%) in 2006-2007 and 18.5% (95% CI, 16.0%-21.2%) in 2016-2017.

CONCLUSIONS

The proportion of the county's pediatric population who underwent vitamin D testing increased from 2002 to 2017, in parallel to the increased incidence of vitamin D deficiency/insufficiency, but the proportion tested that had vitamin D deficiency/insufficiency remained stable over time.

Trends in Vitamin D Status Around the World

Vitamin D status varies across all continents and countries. Vitamin D status usually is adequate in Latin America and Australia, but in contrast it is very low in the Middle East and some countries in Asia. Trends in vitamin D status, whether it improves or declines over the years, carry important messages. Trends usually are small, but can be predictors and indicators of general health. Vitamin D status has improved in the older population in the United States, and improvement relates to dairy use and vitamin D supplements. To the contrary, vitamin D status has declined in the Inuit population of Canada due to a change from a traditional fish diet to a Western diet. A large improvement was seen in Finland after mandatory fortification of dairy products was introduced. Determinants of decline are less sun exposure, increased use of sunscreen, increase of body mass index (BMI), less physical activity, and poor socioeconomic status. Determinants of increase are food fortification with vitamin D and vitamin D supplements. Food fortification can lead to a population-wide increase in vitamin D status as shown by the Finnish example. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

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.

Role of Geographic Risk Factors in COVID-19 Epidemiology: Longitudinal Geospatial Analysis

Objective

To perform a geospatial and temporal trend analysis for coronavirus disease 2019 (COVID-19) in a Midwest community to identify and characterize hot spots for COVID-19.

Participants and Methods

We conducted a population-based longitudinal surveillance assessing the semimonthly geospatial trends of the prevalence of test confirmed COVID-19 cases in Olmsted County, Minnesota, from March 11, 2020, through October 31, 2020. As urban areas accounted for 84% of the population and 86% of all COVID-19 cases in Olmsted County, MN, we determined hot spots for COVID-19 in urban areas (Rochester and other small cities) of Olmsted County, MN, during the study period by using kernel density analysis with a half-mile bandwidth.

Results

As of October 31, 2020, a total of 37,141 individuals (30%) were tested at least once, of whom 2433 (7%) tested positive. Testing rates among race groups were similar: 29% (black), 30% (Hispanic), 25% (Asian), and 31% (white). Ten urban hot spots accounted for 590 cases at 220 addresses (2.68 cases per address) as compared with 1843 cases at 1292 addresses in areas outside hot spots (1.43 cases per address). Overall, 12% of the population residing in hot spots accounted for 24% of all COVID-19 cases. Hot spots were concentrated in neighborhoods with low-income apartments and mobile home communities. People living in hot spots tended to be minorities and from a lower socioeconomic background.

Conclusion

Geographic and residential risk factors might considerably account for the overall burden of COVID-19 and its associated racial/ethnic and socioeconomic disparities. Results could geospatially guide community outreach efforts (eg, testing/tracing and vaccine rollout) for populations at risk for COVID-19.

Prevalence of vitamin D status and its association with overweight or obesity in a population of Colombian children and adolescents

The present study aimed to estimate the prevalence of 25-OH-D status (insufficiency and deficiency) in children and adolescents residing in Bucaramanga, Colombia and to determine its association with excess weight. A case-control study was nested in the SIMBA II cohort in children and adolescents between the ages of 11 and 20 years old. Cases were defined as those children and adolescents with overweight or obesity. The control group was composed of children and adolescents from the same population sample with similar sociodemographic and economic characteristics but without overweight or obesity diagnosis. 25-hydroxyvitamin D (25-OH-D) was quantified in serum using a chemiluminescent microparticle immunoassay. Logistic regression models were used to assess the association between vitamin D status and overweight or obesity adjusted for the main confounding variables. A total of 494 children and adolescents cases were 138 (52⋅17% boys and 47⋅83% girls; median age 16⋅0 [Q1 15; Q3 18]). The median BMI S-Score minors age in the cases was 1⋅36 [Q1 1⋅06; Q3 2⋅00] and BMI (kg/m2) 28⋅0 [Q1 26⋅2; Q3 30⋅8]. The prevalence of vitamin D in the cases was deficiency 16⋅67%, insufficiency 57⋅25%, sufficiency 26⋅09. 25-OH-D insufficiency was associated with overweight or obesity after adjusting for the main confounding variables (OR 1⋅73; 95% CI 1⋅05-2⋅84). Our study concludes that the 25-OH-D insufficiency is common in children and adolescents in Bucaramanga, Colombia, and it was associated with overweight or obesity.

Agreement between area- and individual-level income measures in a population-based cohort: Implications for population health research

Socioeconomic status is an important determinant of health, the measurement of which is of great significance to population health research. However, individual-level socioeconomic factors are absent from much health administrative data, resulting in widespread use of area-level measures in their place. This study aims to clarify the role of individual- and area-level socioeconomic status in Ontario, Canada, through comparison of income measures.

Using data from four cycles (2005–2012) of the Canadian Community Health Survey, we assessed concordance between individual- and area-level income quintiles using percent agreement and Kappa statistics. Individual-level characteristics were compared at baseline. Cumulative adult premature mortality was calculated for 5-years following interview. Rates were calculated separately for area-level and individual-level income, and jointly for each combination of income groups. Multivariable negative binomial models were fit to estimate associations between area- and individual-level income quintile and premature mortality after adjustment for basic demographics (age, sex, interview cycle) and key risk factors (alcohol, smoking, physical activity, and body mass index).

Agreement between individual- and area-level income measures was low. Kappa statistics for same and similar (i.e. ±1 quintile) measures were 0.11 and 0.48, indicating low and moderate agreement, respectively. Socioeconomic disparities in premature mortality were greater for individual-level income than area-level income. When rates were stratified by both area- and individual-level income quintiles simultaneously, individual-level income gradients persisted within each area-level income group. The association between income and premature mortality was significant for both measures, including after full adjustment.

Area-level socioeconomic status is an inappropriate proxy for missing individual-level data. The low agreement between area- and individual-level income measures and differences in demographic profile indicate that the two socioeconomic status measures do not capture the same population groups. However, our findings demonstrate that both individual- and area-level income measures are associated with premature mortality, and describe unique socioeconomic inequities.

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Area- and individual-level income measures may not capture the same groups.

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Area-level socioeconomic status is not a valid proxy for individual-level data.

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Area- and individual-level income are independently meaningful for health outcomes.

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Measures can be used together to fully contextualize socioeconomic status.