Avaliação da densidade mineral óssea em homens portadores de tireoidite crônica autoimune

Abstract

Introduction: Autoimmune chronic thyroiditis (ACT), also known as Hashimoto’s thyroiditis, has been associated with calcitonin deficiency, a hormone involved in the regulation of calcium and phosphorus metabolism. Alterations in the secretion or action of calcitonin and other hormones that regulate mineral homeostasis may impair osteoblasticosteoclastic coupling, affecting bone remodeling processes and potentially leading to reduced bone mass. Objectives: This study aimed to investigate potential alterations in bone mineral density (BMD) in men with ACT, presumably deficient in calcitonin. Methods: Forty men with ACT, aged 25 to 70 years, and followed at a thyroid outpatient clinic, were selected. Of these, 32 underwent laboratory tests and bone densitometry (DXA, Lunar DPX GE Prodigy device); 30 met the inclusion criteria and were compared with 27 euthyroid, healthy men (comparison group, CG). Variables with normal distribution were analyzed using Student’s ttest, while non-normally distributed variables were assessed using the Mann–Whitney test. The chi-square test was applied for categorical variables. Correlations between continuous variables were analyzed using Pearson’s (parametric) and Spearman’s (nonparametric) tests, with a significance level set at p<0.05. Results: Age ranged from 32 to 70 years in the ACT group (median: 52.5) and from 27 to 70 years in the CG (median: 47.0). The mean BMI was 29.0 ± 4.6 in the ACT group and 27.8 ± 3.7 kg/m² in the CG. Both groups exhibited preserved thyroid function and normal levels of calcium, phosphorus, magnesium, parathyroid hormone, and vitamin D. Men with ACT showed significantly lower bone mineral density values, both in absolute terms (BMD) and relative to age (Z-scores), at the skeletal sites assessed. However, these values did not meet the criteria for low bone mass (Z-score < -2.0). No statistically significant differences in T-scores were observed between groups. Conclusion: The possible calcitonin deficiency in men with ACT may exert a subtle but measurable effect on bone mass, as evidenced by lower Z-scores, although without clinical relevance according to conventional criteria for osteopenia and osteoporosis. These findings highlight the importance of individualized bone health assessment in men with ACT, considering the complex interplay of pathophysiological mechanisms such as C-cell dysfunction and compensatory osteometabolic responses involving testosterone, parathyroid hormone, calcitriol, and skeletal aging.