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Haojie Zhang, Yuke Cui, Ruihua Dong, Wen Zhang, Shihan Chen, Heng Wan, Chi Chen, Yi Chen, Yuying Wang, Chunfang Zhu, Bo Chen, Ningjian Wang, and Yingli Lu

Background: Bone is thought to be the reservoir of the human lead burden, and vitamin D is associated with bone turnover. We aimed to explore whether exposure to lower 25-hydroxy vitamin D (25(OH)D) levels was associated with higher blood lead levels (BLLs) by increasing the bone turnover rate in individuals with type 2 diabetes.

Methods: A total of 4103 type 2 diabetic men and postmenopausal women in Shanghai, China, were enrolled in 2018. Their 25(OH)D, β-C-terminal telopeptide (β-CTX), N-MID osteocalcin and procollagen type 1 N-peptide (P1NP) levels were detected. Their BLLs were determined by atomic absorption spectrometry. Mediation analyses were performed to identify the possible role that bone turnover played in the underlying mechanisms.

Results: In both the men and postmenopausal women, all three bone turnover markers were inversely associated with 25(OH)D and positively associated with the BLL (all P<0.01) after adjusting for age, current smoking habits, metabolic parameters, duration of diabetes, vitamin D intake, and use of anti-osteoporosis medication. In the mediation analyses, none of the direct associations between 25(OH)D and BLL was significant for the three bone turnover markers, but all three bone turnover markers were found to be significant mediators of the indirect associations between 25(OH)D and BLL.

Conclusion: The association between vitamin D and BLL was fully mediated by bone turnover markers in type 2 diabetic patients (mediation effect). This finding suggested that vitamin D may protect against blood lead exposure from the bone reservoir by decreasing bone turnover in individuals with type 2 diabetes.

Open access

Xiaojie Wang, Zhiyuan Chen, Ziyi Li, Bo Chen, Yong Qi, Guowei Li, and Jonathan D Adachi

Background

Several epidemiological studies have demonstrated the risk factors for fall, while few studies investigated the association between frailty and risk of fall in diabetic patients aged ≥45 years.

Methods

In this multicity observational study, participants with type 2 diabetes aged ≥45 years were enrolled. Frailty status was measured by a frailty index (FI) of deficit accumulation. We used multivariable regression models to examine the relationship between frailty and fall in diabetic patients, and further investigated the associations between frailty and fall in varied subgroups.

Results

A total of 2049 participants with type 2 diabetes were identified in our study. Our results showed a per-s.d. and a per-0.01 increment of FI were associated with an increased risk of fall, with a fully adjusted OR of 1.89 (95% CI: 1.50, 2.38), 1.06 (95% CI: 1.04, 1.09), respectively. The effects were magnified when frailty was considered as dichotomous, with an OR of 3.08 (95% CI: 2.18, 4.34). In further subgroup analyses, we found that the females, the older, rural residents, individuals with no sitting toilet, people with poor balance performance and those in poor health status were susceptible to fall. Especially, for the risk of fall in the older, a per-s.d. increase of FI corresponded to an OR of 2.46 (95% CI: 1.68, 3.62). When frailty was regarded as a binary variable, the effect increased to 4.62 (95% CI: 2.54, 8.38) in the older subgroup.

Conclusion

Frailty was associated with a higher risk of fall in people with type 2 diabetes, and the effects were higher in vulnerable groups. This evidence suggested that more attention should be paid to vulnerable groups for fall prevention.

Open access

Bo Zhu, Yumei Chen, Fang Xu, Xiaolu Shen, Xuanyu Chen, Jieqiang Lv, and Songying Zhang

Background

Androgens excess results in endoplasmic reticulum (ER) stress, which is an important cause of β cells dysfunction. Here, we investigated the molecular regulation of androgens excess, ER stress, and β-cell function in polycystic ovary syndrome (PCOS).

Methods

PCOS mouse model was established by injection of DHEA. Primary cultured mouse islets were used to detect testosterone (TE)-induced ER stress. The response of ER stress, apoptosis, and hyperinsulinemia were analyzed in INS-1 cells with or without TE exposure. Androgen receptor (AR) antagonist and ER stress inhibitor treatment was performed to evaluate the role of TE in ER stress and proinsulin secretion of PCOS mice.

Results

PCOS mice had higher ER stress in islets. TE exposure induced ER stress and apoptosis significantly through sustaining insulin overexpression in β cells, which in turn impaired proinsulin maturation and secretion. Blocking this process could significantly relieve ER stress and apoptosis and improve insulin homeostasis.

Conclusion

ER stress activated by androgens excess in PCOS contributes to β cell dysfunction and hyperinsulinemia.