Association between BMI and osteoporotic fractures at different sites in Chinese women: a case-control retrospective study in Changsha.

BACKGROUND: Osteoporotic fractures are a growing problem in an aging society. The association between body mass index (BMI) and osteoporotic fractures varies by fracture site and ethnicity. Limited knowledge exists regarding this association in native Chinese, particularly utilizing local databases as reference sources. OBJECTIVE: To investigate the association between BMI and osteoporotic fractures at different sites in Chinese women. METHODS: Three thousand ninety-eight female patients with radiographic fractures and 3098 age- and sex-matched healthy controls without fractures were included in the study. Both of them underwent assessment using dual-energy X-ray absorptiometry (DXA), with BMD measurements calculated using our own BMD reference database. Participants were classified into underweight (BMI < 18.5 kg/m2), normal weight (18.5 ≤ BMI < 24.0 kg/m2), overweight (24 ≤ BMI < 28 kg/m2) and obese (BMI ≥ 28 kg/m2) according to the Chinese BMI classification standard. RESULTS: There were 2296 (74.1%) vertebral fractures, 374 (12.1%) femoral neck fractures, and 428 (13.8%) other types of fractures in the case group. Bone mineral density (BMD) was almost lower in the fracture groups compared to the control groups (p = 0.048 to < 0.001). Compared with normal weight, underweight had a protective effect on total [odds ratio (OR) = 0.61; 95% confidence interval (CI), 0.49 -0.75; P< 0.001], and lumbar fractures (OR = 0.52; 95% CI, 0.41 - 0.67; P < 0.001), while obesity was associated with an increased risk for total (OR = 2.26; 95% CI, 1.85 - 2.76; P < 0.001), lumbar (OR = 2.17; 95% CI, 1.72 - 2.73; P < 0.001), and femoral neck fractures (OR = 4.08; 95% CI, 2.18 - 7.63; P < 0.001). Non-linear associations were observed between BMI and fractures: A J-curve for total, lumbar, and femoral neck fractures, and no statistical change for other types of fractures. Underweight was found to be a risk factor for other types of fracturess after adjusting for BMD (OR = 2.29; 95% CI, 1.09 - 4.80; P < 0.001). Osteoporosis and osteopenia were identified as risk factors for almost all sites of fracture when compared to normal bone mass. CONCLUSIONS: Underweight has a protective effect on total and lumbar spine fractures in Chinese women, while obesity poses a risk factor for total, lumbar, and femoral neck fractures. The effect of BMI on fractures may be mainly mediated by BMD.

Advanced Progress of the Relationship Between Antihypertensive Drugs and Bone Metabolism.

Hypertension and osteoporosis are common comorbidities among elderly individuals. Drug therapy has been widely used in clinical practice as the preferred antihypertensive treatment. Therefore, antihypertensive drugs have become some of the most commonly prescribed drugs in healthcare settings. However, antihypertensive drugs have different effects on bone metabolism. The results of animal and clinical studies on the effects of antihypertensive drugs on osteoporosis or fracture risk are controversial and have aroused widespread concern among clinicians. Recent studies found that angiotensin receptor blockers, selective ß-adrenergic receptor blockers, and thiazide diuretics might improve bone trabecular number and bone mineral density by stimulating osteoblast differentiation, reducing osteoclast generation, and other mechanism. Furthermore, nonselective ß-adrenergic receptor blockers and dihydropyridine calcium channel blockers were found to have no significant relationship with bone mineral density or bone strength, and α-adrenergic receptor blockers and loop diuretics might increase fracture risk by decreasing bone mineral density. This article aimed to review previous animal experiments, clinical studies, and meta-analyses focusing on the effects of different antihypertensive drugs on bone metabolism, and to provide a new approach for the prevention and treatment of osteoporosis.

Exposure to famine in every stage of life and the risk of osteoporosis and fractures later in life: A cross-sectional study.

BACKGROUND AND OBJECTIVE: Data on the association between early-life famine exposure and osteoporosis and fractures remain limited and inconclusive. The aim of this study was to investigate the correlation between famine exposure and osteoporosis and fractures. METHODS: We performed a cross-sectional analysis using the first follow-up survey data from the China Cardiometabolic Disease and Cancer Cohort Study from 2014 to 2016. We classified 4807 Lanzhou participants into seven groups based on their birthday (non-exposed or exposed in the fetal stage, early childhood, mid-childhood, late childhood, adolescence, or early adulthood). And we combined the non-exposed and early-adulthood exposed groups as a control group, which was called "age balanced group". This age-balanced group was used as the control group to further evaluate the risk of osteoporosis and fracture. We used multiple logistic regression to estimate the association between famine exposure and the risk of osteoporosis (T-score ≤ -1.8 by QUS) and self-reported fracture. RESULTS: In women, compared to the age-balanced group, the odds ratios (95 % CI) for the risk of osteoporosis were 1.400(1.034, 1.897), 1.630(1.268, 2.095), 1.707(1.314, 2.218), 2.150(1.732.2.668) and 2.885(2.286,3.641) in the fetal stage, early childhood, mid-childhood, late childhood and adolescence famine-exposed cohorts. In men, no association between famine and osteoporosis was noted with exposed cohort compared with the age-balanced control cohort (p > 0.05). Interestingly, the association between famine exposure and fractures was slightly different from the above results: in women, the odds ratios (95 % CI) for fractures in mid-childhood famine exposure was 1.461(1.082,1.973), in late childhood famine exposure was 1.333(1.035,1.718) and in adolescence famine exposure was 1.607(1.239,2.085). However, compared to the age-balanced control cohort, men exposed to famine in early childhood (OR: 1.801, 95 % CI: 1.010,3.211) had a higher risk of fracture. CONCLUSION: Famine exposure in different life stage has adverse effects on bone health. Famine exposure in not only the period from gestation to infancy, but also childhood and adolescence was associated with an increased risk of osteoporosis, especially in women. Exposure to famine in childhood- (mid and late) and adolescence- life period is associated with fracture in women. But, in men early-childhood famine exposure was only associated with fracture.

Associations of the baseline level and change in glycosylated hemoglobin A1c with incident hypertension in non-diabetic individuals: a 3-year cohort study.

BACKGROUND: Diabetes mellitus increases the risk of developing hypertension. The relationship between glycosylated hemoglobin A1c (HbA1c) level and incident hypertension remains controversial. This study examined the associations of the baseline level and change in the HbA1c level over 3 years with incident hypertension in non-diabetic individuals. METHODS: This community-based cohort study was conducted with 2591 individuals aged 40-75 years without hypertension or diabetes at baseline, who participated in a longitudinal (REACTION) study program. Questionnaires were administered during interviews, and anthropometric and laboratory measurements were performed at baseline (2011) and follow-up (2014-2015). Multivariate logistic regression models were applied to estimate odds ratios (ORs) and 95% confidence intervals (CIs) of incident hypertension. RESULTS: Over a median follow-up period of 3.08 years (interquartile range 3.00, 3.25), 384 (14.82%) subjects developed hypertension. In the fully adjusted linear regression models, change in HbA1c remained significantly associated with changes in systolic blood pressure and diastolic blood pressure [ß-coefficient (95% CI), 4.421 (2.811-6.032), 1.681 (0.695-2.667)]. Logistic regression analyses showed that baseline HbA1c level was positively associated with incident hypertension in the unadjusted model; however, the association was no longer significant after further adjustment. Change in HbA1c was positively associated with the development of hypertension, both as a categorical variable stratified by tertiles [adjusted OR (95% CI) in the highest tertile was 1.690 (1.240-2.303) versus the lowest tertile)] and as a continuous variable [adjusted OR (95% CI), 1.242 (1.106-1.394)], independent of age, sex, body mass index, systolic blood pressure, fasting plasma glucose level, lipid profile, the HbA1c level at baseline and 3-year change in body mass index. CONCLUSIONS: A higher baseline HbA1c level was not an independent risk factor for incident hypertension, whereas the change in HbA1c was independently associated with a greater longitudinal increase in blood pressure and an increased risk of incident hypertension in non-diabetic individuals.

25-Hydroxyvitamin D and Incidence of Type 2 Diabetes from a Chinese Cohort Study.

This study aims to examine whether low serum 25-hydroxyvitamin D [25(OH)D] concentrations are correlated with increased risk of incident type 2 diabetes (T2D) in a Chinese population. The present prospective cohort study included 5,543 participants aged 40-75 y old and is free of diabetes at baseline in Lanzhou city, China. Serum 25(OH)D concentrations were measured. T2D incidence was defined based on obtained results from oral glucose tolerance tests or a self-reported previous diagnosis of diabetes by healthcare professionals. The association between baseline serum 25(OH)D concentrations and incident T2D was investigated using Cox proportional hazards model and restricted cubic spline. Of 5,543 participants (1,433 men and 4,110 women) followed for an average period of 3.9 y, 239 (4.3%) developed diabetes. No significant difference in serum 25(OH)D concentrations was found between individuals who developed diabetes and those who did not (p>0.05). Furthermore, serum 25(OH)D quartiles were not associated with T2D incidence (HR 1.33, 95% CI: 0.89-1.97, p=0.18) after adjusting for body mass index (BMI) and other potential confounders, as well as in subgroups classified with sex (men, women), glucose status (normal glucose tolerance, prediabetes), and BMI (<25 kg/m2, ≥25 kg/m2). The lower serum 25(OH)D concentrations are not associated to a higher risk of incident T2D in the present Chinese cohort after adjusting for BMI and other numerous potential confounding factors.

Metabolic (Dysfunction)-Associated Fatty Liver Disease in Chinese Patients with Type 2 Diabetes from a Subcenter of the National Metabolic Management Center.

BACKGROUND: Few studies have investigated the epidemiological metabolic (dysfunction) associated with fatty liver disease (MAFLD) in China, especially among those with type 2 diabetes. METHODS: We recruited 3553 patients aged 18-75 years with type 2 diabetes who underwent abdominal ultrasound and serum biochemical analyses. Patient information including demographic and anthropometric parameters was also collected. RESULTS: Overall, 63.2% of type 2 diabetic patients had MAFLD. Among the MAFLD patients, the proportions of lean, nonobese, and obese MAFLD were 23.1%, 75.7%, and 24.3%, respectively, and the percentage of previously undiagnosed MAFLD was 42.2%. MAFLD patients were younger, had shorter diabetic duration, and had greater BMI, aspartate aminotransferase (AST), alanine aminotransferase (ALT), fasting insulin, postprandial insulin, total cholesterol, and insulin resistance levels (HOMA-IR and TyG index). Liver fibrosis diagnostic panels revealed that the proportions of elevated AST (≥40 U/L) and ALT (≥40 U/L) were 7.3% and 18.5%, respectively. The distributions of AST-to-platelet ratio index (APRI), fibrosis-4 (FIB-4) index, and nonalcoholic fatty liver disease fibrosis score (NFS) per stage were as follows: APRI-low 55.1%, indeterminate 35.3%, and high 9.5%; FIB-4-low 48.2%, indeterminate 45.3%, and high 6.5%; and NFS-low 15.0%, indeterminate 70.0%, and high 13.0%. CONCLUSIONS: MAFLD is a very common condition and generally had greater frequency of metabolic characteristics among type 2 diabetics in China. Many MAFLD patients were in the "indeterminate" or "high" stage when APRI, FIB-4, and NFS were assessed. Assessment of MAFLD should be included in the management of type 2 diabetes.

Folate ameliorates homocysteine-induced osteoblast dysfunction by reducing endoplasmic reticulum stress-activated PERK/ATF-4/CHOP pathway in MC3T3-E1 cells.

INTRODUCTION: Homocysteine (Hcy) is considered a newly identified risk factor for osteoporosis. Nevertheless, the underlying mechanism of folate (FA), a key factor in the metabolism of Hcy, in protection against osteoblast dysfunction remains unclear. The purpose of this study was to investigate the mechanism by which FA attenuates Hcy-induced osteoblast damage. MATERIALS AND METHODS: The Hcy-induced MC3T3-E1 cells were treated with different concentrations of FA. Cell morphology, cell density, cell proliferation ability, alkaline phosphatase (ALP) activity and mineralization capacity were observed and determined; the gene expression of B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (BAX) and ERS-associated factors, including glucose-regulated protein 78 (GRP-78), activating transcription factor 4 (ATF-4) and growth arrest and DNA damage inducible gene 153 (CHOP/GADD153), were assessed by RT-PCR; and protein levels of GRP-78 and ATF-4 were analyzed by western blotting. RESULTS: Hcy suppressed the proliferation, differentiation and mineralization ability of MC3T3-E1 cells in a concentration-dependent manner and activated the ERS signaling pathway. After intervention with different concentrations of FA, the cell viability and density, ALP activity, number of mineralized nodules, calcium content and Bcl-2 gene expression were all significantly increased, whereas the gene expression of GRP-78, CHOP/GADD153, ATF-4 and Bax was markedly downregulated, and protein levels of GRP-78 and ATF-4 were also markedly decreased. CONCLUSION: The adverse effects of Hcy on osteoblast differentiation are dose dependent. FA not only protects against osteoblasts apoptosis but also has a direct osteogenic effect on Hcy-induced osteoblasts, which could be partially mediated by inhibition of the PERK-activated ERS pathway.

Vitamin D deficiency in diabetes exacerbates longitudinal risk for atherosclerotic cardiovascular disease in Lanzhou, China.

BACKGROUND AND OBJECTIVES: Vitamin D deficiency has been considered a risk factor for atherosclerotic cardiovascular disease (ASCVD). The aim of this study was to investigate the correlation between serum 25(OH)D concentration and the risk of ASCVD in Chinese, especially in Type 2 diabetes mellitus (T2DM) patients. METHODS AND STUDY DESIGN: Based on the "REACTION" study conducted in 2011, some 9,014 Lanzhou residents aged 40-75 years were followed from 2014 to 2016. A total of 7,061 with complete data were analyzed. Baseline population was classified into four groups based on 25(OH)D quartiles. Cox proportional hazard models were used to estimate relations between 25(OH)D concentration and ASCVD. RESULTS: The prevalence of vitamin D deficiency [25(OH)D <20 ng/mL] was 75.1%. Followed-up for 3.3 years, those with the lowest of 25(OH)D concentration had higher rates of ASCVD (HR: 1.748, 95% CI: 1.149-2.660, p<0.01). A 10 ng/mL increase in baseline serum 25(OH)D was accompanied by a 24 % decrease in ASCVD risk (HR: 0.760, 95% CI: 0.590-0.980, p<0.05). For 25(OH)D and ASCVD risk with glycaemic status, low 25(OH)D plus T2DM was highly associated with ASCVD (HR: 2.296, 95% CI: 1.246-4.232, p<0.01). With diabetes, ASCVD risk decreased by 36% when serum 25(OH)D increased by 10 ng/mL (HR: 0.644, 95% CI: 0.440-0.941, p<0.05). CONCLUSIONS: Serum 25(OH)D is independently and inversely associated with the risk of ASCVD in Lanzhou Chinese, especially those with T2DM. Maintaining sufficient levels of vitamin D may be an effective measure in ASCVD prevention.

Correlation of serum vitamin D with lipid profiles in middle-aged and elderly Chinese individuals.

BACKGROUND AND OBJECTIVES: Deficiency of vitamin D has been associated with various health conditions. The purpose of this study was to evaluate the associations between the serum 25OHD concentration and lipid profiles in Chinese individuals. METHODS AND STUDY DESIGN: Serum 25OHD and lipid profiles were obtained for a cross sectional sample of 10100 individuals aged 40-75 years from Lanzhou city, which is located in western China. Linear-by-linear association, partial correlation analysis and multiple logistic regression analysis were used to evaluate associations between serum 25OHD concentration and lipid profiles. RESULTS: 10038 subjects aged 40- 75 years were included in the study. The 25OHD deficient and insufficient groups had higher TC, LDL-C and TG when compared to the optimal group. The dyslipidemia rates of vitamin D deficiency, insufficiency, and sufficiency groups were 45.4%, 41.6%, 38.8%, respectively. The prevalence rates of dyslipidemia, high cholesterol, high LDL-C, hypertriglyceridemia and mixed type hyperlipidemia exhibited decline trend in vitamin D deficiency, insufficiency and sufficiency groups. The correlation coefficients in between TC and 25OHD, LDL-C and 25OHD, TG and 25OHD were -0.033, -0.022, -0.044, respectively. Low 25OHD levels were associated with the risk of onset of dyslipidemia [OR 1.225 (95% CI 1.075-1.397), p=0.002] in the logistical regression analyses. CONCLUSIONS: Deficient serum 25OHD is associated with higher TC, LDL-C, and TG in middle-aged and elderly Chinese individuals. These findings suggest that low 25OHD levels observationally is simply a marker for elevated atherogenic lipoproteins and question a role for vitamin D supplementation in the prevention of cardiovascular disease.

[Correlation of type 2 diabetes and impaired glucose regulation with chronic kidney disease in middle-aged and elderly individuals].

OBJECTIVE: To explore the correlation of different glucose metabolism statues with chronic kidney disease (CKD) in middle-aged and elderly individuals in Lanzhou. METHODS: Based on the baseline data of REACTION Study in Lanzhou area, we randomly sampled 10 038 residents aged 40-75 years in 3 communities in Lanzhou, who were classified into normal glucose tolerance (NGT), impaired glucose regulation (IGR) and diabetes groups. The estimated glomerular filtration rate (eGFR) and urinary albumin-to-creatinine ratio (ACR) were used to assess the renal function and albuminuria, respectively. Binary logistic regression was performed to analyze the contribution of the risk factors to CKD. Polynominal regression was used to determine the trends of eGFR with the increment of ACR. RESULTS: Among all the participants, the prevalences of albuminuria, CKD and renal insufficiency (RI) were 26.2%, 27.4% and 2.5%, respectively. The prevalence of albuminuria, CKD and RI were significantly higher in the diabetes group than in IGR and NGT groups (P < 0.05). In IGR group, age, hypertension, and hypertriglyceridemia were positively correlated with the risk of RI (OR: 1.113, 1.904, and 2.608, respectively; P < 0.05). In diabetes group, age, coronary heart disease, obesity, hypertriglyceridemia, and elevated LDL-C level were positively correlated with the risk of RI (OR: 1.069, 2.535, 3.359, 1.827, and 2.690, respectively; P < 0.05). Logistic regression analysis showed that diabetes mellitus significantly increased the risk of albuminuria (OR: 1.543, P=0.000) and RI (OR: 1.446, P=0.005). Logistic regression analysis and multivariate regression analysis showed that although the deterioration trends of eGFR were similar in diabetes group and IGR group, IGR was not a significant risk factor for albuminuria or RI (OR:1.057, P=0.355; OR: 0.918, P=0.614). CONCLUSIONS: Diabetes mellitus is a significant risk factor for albuminuria and RI, while IGR is not. Screening for albuminuria and eGFR is highly recommended for individuals with diabetes, hypertension, and obesity, especially in women and the elderly population.

Matrine induces papillary thyroid cancer cell apoptosis in vitro and suppresses tumor growth in vivo by downregulating miR-182-5p.

Matrine is a natural product extracted from the root of Sophora flavescens that has been shown to be a promising alternative drug in different types of cancer. Here, we aimed to investigate the antitumor effects of matrine on human papillary thyroid cancer (PTC) and explore the underlying molecular mechanisms. Our data demonstrated the following findings. (a) The expression of miR-182-5p was significantly upregulated in PTC tissues and cell lines. (b) Matrine inhibited the expression of miR-182-5p and induced the apoptosis of TCP-1 and BCPAP cells in a dose-dependent manner. (c) Matrine increased caspase3 expression levels and reduced Bcl-2 expression levels in both TCP-1 and BCPAP cells. (d) Matrine appreciably inhibited PTC tumor growth in vivo. (e) After miR-182-5p overexpression, matrine-induced apoptosis and caspase3 activation were inhibited, and the matrine-induced decrease in Bcl-2 expression was abolished. (f) Overexpression of miR-182-5p counteracted the inhibitory effects of matrine on PTC tumor growth. In conclusion, these results demonstrate that matrine exerts antitumor effects possibly by inducing the apoptosis of TCP-1 and BCPAP cells, decreasing the level of Bcl-2, activating caspase3 and suppressing PTC tumor growth by downregulating the expression of miR-182-5p. These findings explain the anticancer mechanisms of matrine in PTC and identify miR-182-5p as an effective target of matrine in PTC treatment.

Natural history of mild subclinical hypothyroidism in a middle-aged and elderly Chinese population: a prospective study.

Subclinical hypothyroidism (SCH) has a high global prevalence. Most SCH patients have mild cases (thyrotropin ≤10 mIU/L). Treatment recommendations for mild SCH are controversial, which raises concerns about the natural history of mild SCH. We aimed to clarify the natural history of mild SCH. This is a prospective population-based study. We measured thyroid function in 11,000 participants in the REACTION study and followed 505 newly diagnosed mild SCH patients aged 40-years or older between 2011 and 2014. Logistic regression analysis was used to seek baseline parameters associated with the natural outcomes of mild SCH. Among 505 mild SCH patients, 221 (43.8%) had persistent SCH, 251 (49.7%) reverted to euthyroidism, and 17 (3.4%) progressed to overt hypothyroidism (OH). Patients with higher baseline total cholesterol (TC, between 201.0-240.0 mg/dL or >240.0 mg/dL vs. <201.0 mg/dL, p = 0.048 and 0.006, respectively) or positive thyroid peroxidase antibodies (TPOAb, p = 0.009) had higher risks of progression to OH, while those with higher baseline creatinine (CR, between 0.71-0.80 mg/dL or >0.80 mg/dL vs. ≤0.65 mg/dL, p = 0.031 and 0.004, respectively), higher baseline thyrotropin (≥7 mIU/L, p < 0.001) or older (>60 years vs. ≤50 years, p = 0.012) had lower odds of reverting to euthyroidism. In conclusion, TPOAb and TC seem to be more important predictors of progression to OH than initial thyrotropin, whereas high baseline thyrotropin or CR were negative correlated with reversion to euthyroidism. The prognostic value of TC and CR in mild SCH should be considered.

High prevalence of vitamin D deficiency among middle-aged and elderly individuals in northwestern China: its relationship to osteoporosis and lifestyle factors.

PURPOSE: Vitamin D deficiency has reached epidemic proportions; this deficiency has been associated with osteoporosis and certain lifestyle factors in adults. This relationship is not well documented among the Lanzhou population in northwest China. This study sought to determine the prevalence of vitamin D deficiency and its risk factors in addition to its relationship with osteoporosis in a Chinese population living in Lanzhou. METHODS: This cross-sectional study involved 2942 men and 7158 women aged 40-75years who were randomly selected from 3 communities in the Lanzhou urban district and examined medically. Levels of 25-hydroxy-vitamin D [25(OH)D] and other parameters were measured according to detailed inclusion criteria. Vitamin D deficiency was defined as serum 25(OH)D levels below 20ng/mL. Calcaneus bone mineral density (BMD) was measured by quantitative ultrasound (QUS). RESULTS: The prevalence of vitamin D deficiency (25(OH)D levels <20ng/mL) was present in 75.2% of the entire study population. Vitamin D deficiency was more prevalent in women (79.7%) than in men (64%; P<0.001). Multiple logistic regression analysis revealed that the significant predictors of vitamin D deficiency included coronary heart disease (CHD), obesity, dyslipidemia, older age, female sex, and smoking (all P<0.05), whereas tea intake, moderate physical activity, milk intake, vitamin D supplementation and sun exposure were protective (all P<0.05). No significant difference in calcaneus BMD measured by QUS was noted between subjects with <20ng/mL and ≥20ng/mL vitamin D levels (0.53±0.13 vs. 0.54±0.13; P=0.089). The risk of having osteoporosis did not increase when vitamin D levels decreased from ≥20ng/mL to <20ng/mL after multiple adjustments (OR=1.00; 95% CI 0.85-1.16; P=0.357). CONCLUSIONS: Vitamin D deficiency is prevalent in the middle-aged and elderly northwestern Chinese population and is largely attributed to CHD, obesity, dyslipidemia, older age, female sex, and smoking. Reduced 25(OH)D levels are not associated with an increased osteoporosis risk.

The status of 25-hydroxyvitamin D across the spectrum of glucose tolerance among middle-aged and elderly Chinese individuals.

CONTEXT: Although vitamin D status and its inverse association with diabetes among White people have been recognized, little research on vitamin D status has been well conducted in Chinese individuals based on glucose tolerance. OBJECTIVE: To compare the vitamin D status of Chinese individuals aged 40-75 years based on the glucose tolerance status. DESIGN AND METHODS: Serum 25OHD was measured in a cross-sectional sample of 10 038 individuals aged 40-75 years from Lanzhou city, which is located in western China. RESULTS: People with normal glucose tolerance (NGT, n = 4744), prediabetes (n = 2808) or diabetes (n = 2486) aged 40-75 years were included in the study. The difference in 25OHD concentration between people with NGT and prediabetes was not significant (16·5 vs 16·0 ng/ml, P = 0·773), but the 25OHD concentration of diabetes was higher than that of subjects with NGT (16·5 vs 16·5 ng/ml, P = 0·025) and prediabetes (16·5 vs 16·0 ng/ml, P = 0·032) after adjusting confounders. There was no difference in the prevalence of vitamin D deficiency between people with NGT and diabetes (74·7% vs 74·0%, P = 0·535), but the prevalence of vitamin D deficiency of prediabetes was higher than that of people with NGT (77·0% vs 74·7%, P = 0·024) and diabetes (77·0% vs 74·0%, P = 0·012). CONCLUSIONS: Although vitamin D status was significantly different across the spectrum of glucose tolerance in middle-aged and elderly Chinese individuals, the difference was not clinically significant. The results, however, highlight the very high prevalence of vitamin D deficiency in this population and should raise the awareness of this important public health issue among health-care providers.

Metformin reverses the deleterious effects of high glucose on osteoblast function.

An association has been previously established between uncompensated diabetes mellitus and the loss of bone mineral density and/or quality. In the present study, we examined the effects of different concentrations of glucose (5.5, 11, 22, and 44 mmol/L) with or without metformin (10-640 micromol/L) on rat primary osteoblasts cultured in an osteogenic medium. With 11 mmol/L glucose, cellular proliferation, alkaline phosphatase (ALP) activity, the number of nodules formed, and calcium deposition in mineralized nodules were increased significantly; intracellular reactive oxygen species (ROS) and apoptosis were slightly reduced, although these reductions were not statistically significant. At higher concentrations of glucose (22 and 44 mmol/L), cellular proliferation, ALP activity, the number of nodules formed, and calcium deposition were greatly reduced; ROS and apoptosis were significantly increased in a dose-dependent manner. Metformin markedly increased cellular proliferation, ALP activity, calcium deposition, and the number of nodules formed and inhibited ROS and apoptosis in all glucose groups. Moreover, we assessed the gene expression levels of Runx2, IGF-1, and IGF-1R. Eleven micromole per liter glucose stimulated Runx2 and IGF-1 expression; 44 mmol/L glucose inhibited Runx2, IGF-1, and IGF-1R expression. Metformin stimulated the expression of Runx2 and IGF-1 in three glucose groups, but it did not affect IGF-1R. In conclusion, our findings suggest that the dual effects of glucose on cell proliferation and development are dose dependent. Metformin not only significantly decreased intracellular ROS and apoptosis, but also had a direct osteogenic effect on osteoblasts at all glucose concentrations, which could be partially mediated via promotion of Runx2 and IGF-1 expression.