Is it necessary for all samples to quantify 25OHD2 and 25OHD3 using LC-MS/MS in clinical practice?

Serum 25-hydroxyvitamin D status of a large Chinese population from 30 provinces by LC-MS/MS measurement for consecutive 3 years: differences by age, sex, season and province

PURPOSE

We aimed to describe the vitamin D status and its distribution in different age groups, sexes, seasons, and provinces of a large Chinese population.

METHODS

This study retrospectively analyzed 1,528,685 results of serum 25-hydroxyvitamin D (25(OH)D) in the central laboratory of KingMed Diagnostics. The samples were from the individuals aged 0-119 years old in 30 provinces of China. Serum 25(OH)D was measured by an accurate commercial liquid chromatography-tandem mass spectrometry (LC-MS/MS) method from January 2017 to December 2019. The subjects were stratified by age, sex, the season of blood collection, and the province of residence.

RESULTS

The median 25(OH)D concentration was 25.5 ng/mL (interquartile range (IQR) 18.7-32.7 ng/mL) in males and 20.8 ng/mL (IQR 14.4-28.2 ng/mL) in females. Overall, the median 25(OH)D concentration decreased with age in both males and females. Males had a 0.2-2.4 ng/mL higher median 25(OH)D concentration than females in different age groups. Vitamin D deficiency (25(OH)D < 15 ng/mL for the individuals under 14 years old; < 20 ng/mL for the individuals over 14 years old) was found in 21.3% of males and 43.6% of females. Significant seasonal variation of serum 25(OH)D concentrations was repeatedly observed in 3 years, with median concentration higher in summer (25.3 ng/mL (IQR 19.3-31.9 ng/mL)) and lower in winter (18.5 ng/mL (IQR 12.3-26.6 ng/mL)). Vitamin D status varied by province. The median 25(OH)D concentration was the highest in Hainan (31.0 ng/mL (IQR 24.9-39.2 ng/mL)) and the lowest in Qinghai (14.4 ng/mL (IQR 9.6-20.0 ng/mL)). 25(OH)D₂ was detected in 12.2% of the results, and no significant seasonal variation was observed.

CONCLUSION

In China, vitamin D deficiency is prevalent in the population participating in clinical vitamin D measurement. Age and sex differences in vitamin D levels were observed in our study. Seasonal variation and provincial differences are important aspects of serum vitamin D status. 25(OH)D₂ cannot be ignored entirely in clinical measurement practice in China.

Spatial distribution differences of 25-hydroxyvitamin D in healthy elderly people under the influence of geographical environmental factors

The main targets of this were to screen the factors that may influence the distribution of 25-hydroxyvitamin D[25(OH)D] reference value in healthy elderly people in China, and further explored the geographical distribution differences of 25(OH)D reference value in China. In this study, we collected the 25(OH)D of 25,470 healthy elderly from 58 cities in China to analyze the correlation between 25(OH)D and 22 geography secondary indexes through spearman regression analysis. Six indexes with significant correlation were extracted, and a ridge regression model was built, and the country’s urban healthy elderly’25(OH)D reference value was predicted. By using the disjunctive Kriging method, we obtained the geographical distribution of 25(OH)D reference values for healthy elderly people in China. The reference value of 25(OH)D for healthy elderly in China was significantly correlated with the 6 secondary indexes, namely, latitude (°), annual temperature range (°C), annual sunshine hours (h), annual mean temperature (°C), annual mean relative humidity (%), and annual precipitation (mm). The geographical distribution of 25(OH)D values of healthy elderly in China showed a trend of being higher in South China and lower in North China, and higher in coastal areas and lower in inland areas. This study lays a foundation for further research on the mechanism of different influencing factors on the reference value of 25(OH)D index. A ridge regression model composed of significant influencing factors has been established to provide the basis for formulating reference criteria for the treatment factors of the vitamin D deficiency and prognostic factors of the COVID-19 using 25(OH)D reference value in different regions.

A robust method for simultaneous measurement of serum 25(OH)D, 1,25(OH)2 D, and 24,25(OH)2 D by liquid chromatography-tandem mass spectrometry with efficient separation of 3-epi analogs, 23R,25(OH)2 D3 , and 4β,25(OH)2 D3

BACKGROUND

This study aimed to establish a robust, simple method to detect 25-hydroxyvitamin D₃ (25(OH)D₃ ), 25-hydroxyvitamin D₂ (25(OH)D₂ ), 1,25-dihydroxyvitamin D₃ (1,25(OH)₂ D₃ ), 1,25-dihydroxyvitamin D₂ (1,25(OH)₂ D₂ ), 24,25-dihydroxyvitamin D₃ (24,25(OH)₂ D₃ ), and 24,25-dihydroxyvitamin D₂ (24,25(OH)₂ D₂ ) simultaneously with efficient separation of 3-epi 25(OH)D₃ , 3-epi 24,25(OH)₂ D₃ , 23R,25(OH)₂ D₃ , and 4β,25-dihydroxyvitamin D₃ (4β,25(OH)₂ D₃ ) by liquid chromatography-tandem mass spectrometry (LC-MS/MS).

METHOD

This method was validated according to procedures established by Clinical and Laboratory Standards Institute (CLSI) and then applied in healthy population to determine the distribution of the vitamin D metabolites by LC-MS/MS.

RESULTS

The total-run CV% of 25(OH)D₃ , 25(OH)D₂ , 24,25(OH)₂ D₃ , 24,25(OH)₂ D₂ , 1,25(OH)₂ D₃ , and 1,25(OH)₂ D₂ were 6.30%-8.40%, 5.00%-8.40%, 5.90%-9.00%, 5.60%-9.00%, 5.60%-8.00%, and 7.00%-9.70%, respectively. The linearity correlation coefficients r of these six vitamin D metabolites were >0.99. The matrix effects of 25(OH)D₃ , 25(OH)D₂ , 24,25(OH)₂ D₃ , 24,25(OH)₂ D₂ , 1,25(OH)₂ D₃ , and 1,25(OH)₂ D₂ were 90.6%-103.3%, 97.3%-106.3%, 90.7%-106.3%, 100.7%-114.5%, 97.9%-104.6%, and 97.0%-111.0%. The trueness values of 25(OH)D₃ , 25(OH)D₂ , and 24,25(OH)₂ D₃ were 93.8%-103.0%, 101.0%, and 96.3%-100%, respectively.

CONCLUSION

This study successfully established an efficient, accurate, robust method for simultaneous measurement of serum 25(OH)D, 1,25(OH)₂ D, and 24,25(OH)₂ D by LC-MS/MS with efficient separation of 3-epi analogs, 23R,25(OH)₂ D₃ , and 4β,25(OH)₂ D₃ .

Sterol metabolism and protein metabolism are differentially correlated with sarcopenia in Asian Chinese men and women

OBJECTIVES

Our aim was to investigate the prevalence and predictive variables of sarcopenia.

METHODS

We recruited participants from the Peking Union Medical College Hospital Multicenter Prospective Longitudinal Sarcopenia Study (PPLSS). Muscle mass was quantified using bioimpedance, and muscle function was quantified using grip strength and gait speed. Logistic regression revealed the relationships between sarcopenia and nutritional, lifestyle, disease, psychosocial and physical variables.

RESULTS

The prevalence of sarcopenia and sarcopenic obesity was 9.2%-16.2% and 0.26%-9.1%, respectively. Old age, single status, undernourishment, higher income, smoking, low physical activity, poor appetite and low protein diets were significantly associated with sarcopenia. Multiple logistic regression analysis showed that age was a risk factor for all stages of sarcopenia, and participants above 80 years were greater than fivefold more susceptible to sarcopenia, while lower physical activity was an independent risk factor. The optimal cut-off value for age was 71 years, which departs from the commonly accepted cut-off of 60 years. Female participants were greater than twofold less susceptible to sarcopenia than male participants. The sterol derivative 25-hydroxyvitamin D was associated with fourfold lower odds of sarcopenia in male participants. Several protein intake variables were also correlated with sarcopenia. Based on these parameters, we defined a highly predictive index for sarcopenia.

CONCLUSIONS

Our findings support a predictive index of sarcopenia, which agglomerates the complex influences that sterol metabolism and nutrition exert on male vs female participants.

Ethnic, geographic, and seasonal differences of vitamin D status among adults in south-west China

Background

There are limited data on vitamin D status of Sichuan province, and no investigation has been carried out on the correlations of 25(OH)D and BTMs between healthy Hans and Tibetans of Sichuan province. This study aimed to examine 25(OH)D levels around Sichuan province and to assess differences by ethnicity, age, gender, sunlight exposure, geographic location, and seasons.

Methods

Blood samples from 2317 healthy adults aged of 18 to 75 years and of Han and Tibetan ethnicities were collected in six regions and during four seasons. Serum 25(OH)D₂ and 25(OH)D₃ levels were measured by LC‐MS/MS method. Serum total P1NP and β‐CTX were measured by immunoassay.

Results

Participants aged 18‐40 years showed significantly lower 25(OH)D levels than participants aged 41‐75 years old (P < .0001). The median serum 25(OH)D level for males was significantly higher than that of females (P < .0001). Serum 25(OH)D levels among four seasons and different districts varied significantly (P < .0001). In addition, the 25(OH)D level of Tibetans was significantly lower than that of Hans, while the serum total P1NP and β‐CTX levels of Tibetans were significantly higher than those of Hans (P < .0001).

Conclusion

Adult population was more common to have vitamin D deficiency/insufficiency among Tibetans, females, north regions and in spring and winter.

Data mining: Seasonal fluctuations and associations between thyroid stimulating hormone and lipid profiles

OBJECTIVE

Thyroid stimulating hormone (TSH) is associated with lipid metabolism. In this study, we aimed to evaluate seasonal variations and the association between TSH and lipid profiles based on clinical big data.

METHOD

This observational, retrospective big data study enrolled a total of 20,192 individuals who visited Peking Union Medical College Hospital for routine health check-ups from 2014 to 2018. Demographic, medical history, common biochemical analytes, and thyroid related test data were obtained. A Kruskal-wallis analysis was used to compare the differences in total cholesterol (TC), triglycerides (TG), high density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) by TSH quartiles. Spearman correlation analysis was used to evaluate the association between TSH and lipid profiles as well as temperature.

RESULTS

TC and LDL did not vary significantly with TSH concentration; however, TG and HDL-C did. TSH concentration showed weak positive correlation with serum TC, TG, and HDL-C but not with LDL-C. Serum TC concentration was positively correlated with TG and LDL-C. TG was positively correlated with LDL-C but negatively correlated with HDL-C. HDL-C was negatively correlated with LDL-C. TSH and lipid profiles showed seasonal fluctuations. Monthly median TSH, TC, and LDL-C peaked in winter and dropped to a minimum in summer. The correlation coefficient (r) between the average monthly temperature and TSH, TC, TG, HDL-C, and LDL-C was -0.424 (p = 0.001), -0.539 (p < 0.001), -0.020 (p = 0.880), -0.199 (p = 0.127), and -0.442 (p < 0.001), respectively.

CONCLUSION

Seasonal variation was observed in both TSH and lipids. Apart from the seasonal variation of TC and LDL-C, our results also have clinical interpretation. It suggested that it may not reflect the real status of lipids during and immediately after the Spring festival. Thus, in order to diagnosis of hypercholesterolemia, re-testing was needed later to provide the precision diagnostic, monitoring and treatment.

Rapid liquid chromatography-tandem mass spectrometry method for determination of 24,25(OH)2D and 25OHD with efficient separation of 3-epi analogs

This study establishes and validates a rapid method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) without derivatization steps to simultaneously measure of 24,25(OH)₂D₂, 24,25(OH)₂D₃, 25OHD₂, and 25OHD₃, while efficiently separating the 3-epi analogs. Samples were prepared by precipitation and liquid-liquid extraction. The linearity, precision, accuracy, recovery and matrix effect of the method were thoroughly evaluated according to the Clinical & Laboratory Standards Institute guidelines. Additionally, the four vitamin D metabolites in the serum of 38 apparently healthy Chinese volunteers were evaluated. The total analysis time was 8.0 min, with efficient separation of 3-epi 24,25(OH)₂D₃ and 3-epi 25OHD₃, without interference from isomers such as 23,25(OH)₂D₃ or 1,25(OH)₂D₂, 1,25(OH)₂D₃. Good reproducibility was obtained for all four metabolites with within-run coefficient variations (CVs) of 4.07%-6.55%, 4.26%-7.84%, 2.46%-7.21%, and 4.90%-6.87% for 25OHD₃, 25OHD₂, 24,25(OH)₂D₃, and 24,25(OH)₂D₂, respectively, and the total CVs were 4.29%-6.64%, 6.14%-7.84%, 4.33%-7.21%, 5.82%-9.90%, respectively. The limit of quantification was 0.625 ng/mL for 25OHD₃ and 25OHD₂, and 0.5 ng/mL for 24,25(OH)₂D₃ and 24,25(OH)₂D₂. The relative bias of the LC-MS/MS method compared to the certified results of SRM 972a for 25OHD₃, 25OHD₂ and 24,25(OH)₂D₃ was -2.21% to 1.01%, 3.38% to 6.73%, and -7.72% to -3.9%, respectively. The mean±SD values for 25OHD, 24,25(OH)₂D and 25OHD/24,25(OH)₂D in the volunteers were 13.5±4.4 ng/mL(range:7.6-27.5 ng/mL), 0.84±0.42 ng/mL (range:0.26-2.1 ng/mL), and 18±7(range:8-37), respectively. Thus, a simple, precise LC-MS/MS method for appropriate retention and separation of vitamin D metabolites and their epi analogs was developed.