Sexual Dimorphism for the Association between Vitamin D and Insulin Resistance in Chinese People

In Situ Preservation of Parathyroid Gland With Vasculature for Papillary Thyroid Carcinoma Is Associated With Higher PTH Levels After Total Thyroidectomy

PURPOSE

To evaluate the impact of parathyroid gland vasculature preservation in-situ technique (PGVPIST) on postoperative parathyroid hormone (PTH) and calcium plasma levels in thyroid patients undergoing total thyroidectomy for papillary thyroid carcinoma (PTC).

STUDY DESIGN

Retrospective cohort study.

METHODS

Patients with PTC who underwent total thyroidectomy by either the conventional technique (group 1, January 2019 to January 2020) or PGVPIST (group 2, January 2020 to January 2021) were compared. Postoperative blood calcium levels and PTH levels were assessed in these groups.

RESULTS

Totally 149 patients with consecutive PTC underwent total thyroidectomy, including 60 patients in group 1 and 89 patients in group 2. Postoperative serum calcium levels in group 1 were insignificantly lower than in group 2 at day 1 (2.18 ± 0.02 vs 2.15 ± 0.01 mmol/L) and day 30 (2.27 ± 0.02 vs 2.38 ± 0.11) after surgery. But postoperative serum PTH levels in group 1 were significantly lower than that in group 2 at day 1 (23.68 ± 2.54 vs 31.46 ± 2.11 pg/mL) and day 30 (45.63 ± 3.21 vs 55.65 ± 2.89 pg/mL) after surgery.

CONCLUSION

Parathyroid gland vasculature preservation in-situ technique for PTC is associated with higher PTH level after total thyroidectomy. The parathyroid gland vasculature mostly strongly adheres with adjacent thyroid parenchyma. Therefore, deferred processing of tiny thyroid parenchyma of parathyroid gland vessels is essential to prevent devascularization.

Sex-Dependent Association of Vitamin D With Insulin Resistance in Humans

BACKGROUND

Animal studies suggested that vitamin D might decrease insulin resistance. Estrogen increased insulin sensitivity and glucose tolerance in rodents. However, sex-specific association of vitamin D with insulin resistance in humans remains unclear.

OBJECTIVES

To investigate the sex-dependency of the association of insulin resistance and 25-hydroxyvitamin D [25(OH)D] in a large Caucasian population.

METHODS

Cross-sectional study from out-patients' blood samples with measurements of 25(OH)D and homeostatic model assessment of insulin resistance (HOMA-IR) drawn at exactly the same day (n = 1887). This cohort was divided into 3 groups: (1) group with vitamin D deficiency (n = 1190), (2) group with vitamin D sufficiency (n = 686), and (3) vitamin D excess groups (n = 11); the vitamin D excess group was excluded from further analysis due to the small size.

RESULTS

Analysis of the entire study population showed that serum 25(OH)D was inversely associated with HOMA-IR [Spearman correlation coefficient (rs) = -0.19, P < 0.0001]. When considering the vitamin D status, this association was only seen in the vitamin D deficiency group but not in the vitamin D sufficient group. The correlation was sex-dependent: HOMA-IR was inversely correlated with vitamin D in women with vitamin D deficiency (rs = -0.26, P < 0.0001) but not in men with vitamin D deficiency (rs = 0.01, P = 0.714). After multivariate linear regression analysis considering confounding factors, this relationship was again only seen in women.

CONCLUSION

Vitamin D was inversely and independently associated with insulin resistance only in women with vitamin D deficiency. Based on our data, we suggest that in particular vitamin D deficient women might benefit from vitamin D substitution by improving insulin resistance. This, however, needs to be proven in adequately designed double-blind placebo-controlled clinical studies.