Lack of Influence of Thyroid Hormone on Bone Mineral Density and Body Composition in Healthy Euthyroid Women

Abstract

The objective of this study was to evaluate whether evolution of bone mineral density (BMD) is associated with the thyroid hormone profile in a cohort of euthyroid women with no other known diseases within 1 year. Methods: This was a prospective cohort study conducted at the University of Campinas, Brazil. We used a database with 52 women aged 20-39 who were followed for 1 year in a family planning outpatient clinic. The inclusion criteria were body mass index (BMI) <30 kg/m 2 , no known diseases/medication use, fasting glucose <100 mg/dl, and 2 h glucose after a 75 g oral glucose load <140 mg/dl. The women were divided into groups of normal weight (n = 30) and overweight (n = 22). The main outcomes were BMD measured by dual-energy x-ray absorptiometry (DXA) and thyroid hormone profile (thyrotropin TSH, free triiodothyronine FT3, free thyroxine FT4, and T3/T4 ratio); other variables were body composition (DXA), calcium metabolism markers, and life habits. We used a repeated measures analysis of variance (ANOVA) and multiple regression analyses to evaluate associations. Results: At the baseline data collection, overweight women showed a higher T3/T4 ratio, leptin, calcium, BMD in the lumbar spine and total femur, total mass, mass, and percentage of fat mass than normal weight women. At 12 months, both groups had increased FT4, calcium, ALP, femoral neck BMD, and total mass by time effect. The normal weight group presented a decrease of vitamin D when compared to the baseline. Increased BMD of the femoral neck was associated with moderate coffee intake, and as such, there were no associations found between this increase and the thyroid hormone profile. Leptin and ALP were associated with total mass variation, while leptin and PTH were associated with fat mass variation. The normal BMI was inversely associated with the variation of total mass, mass, and percentage of fat mass, and engaging in regular physical activity was inversely associated with fat mass variation. Conclusions: In this sample of euthyroid healthy women who were both normal weight and overweight, the thyroid hormone profile was not associated with variations in bone mineral density and body composition after a 1 year follow-up.

Association between obesity and risk of fracture, bone mineral density and bone quality in adults: A systematic review and meta-analysis

“…Fifty-four studies were also discarded because the full-text was not available. The full-text of the remaining 487 reports was assessed for eligibility: 353 studies were excluded, leaving 134 for inclusion in the systematic review [ 20 – 22 , 25 , 52 – 181 ]. All included studies were in English or French.…”

“…The kappa statistic was 0.82, displaying a strong inter-reviewer agreement for the full-text selection. Finally, 121 studies were included in the meta-analysis [ 20 – 22 , 25 , 52 – 153 , 163 – 167 , 169 , 171 – 173 , 175 , 177 – 181 ]: 13 [ 154 – 162 , 168 , 170 , 174 , 176 ] were excluded because data was missing, could not be transformed, or could not be obtained from corresponding authors.…”

“…Lumbar spine aBMD by DXA . Lumbar spine aBMD measured by DXA was reported in 56 studies [ 20 – 22 , 52 , 54 , 56 , 59 – 61 , 67 – 72 , 78 , 81 , 84 , 85 , 87 – 89 , 92 – 94 , 97 , 100 , 103 , 106 – 108 , 110 , 112 – 115 , 118 , 120 , 121 , 124 , 126 , 128 , 130 – 132 , 134 , 135 , 142 – 144 , 148 , 150 – 153 , 163 , 167 , 173 , 177 – 181 ], including 29,420 participants. Obesity was associated with increased lumbar spine aBMD in postmenopausal women (n = 27: MD = 0.07 g/cm 2 , 95% CI: 0.05, 0.09, P<0.00001, I 2 = 92%), premenopausal women (n = 17: MD = 0.07 g/cm 2 , 95% CI: 0.04, 0.09, P<0.0001, I 2 = 90%), men (n = 8: MD = 0.06 g/cm 2 , 95% CI: 0.04, 0.08, P<0.00001, I 2 = 48%), and in studies combining men and women (n = 12: MD = 0.06 g/cm 2 , 95% CI: 0.03, 0.08, P<0.00001, I 2 = 93%) ( ...…”

Within-Person Variation in Serum Thyrotropin Concentrations: Main Sources, Potential Underlying Biological Mechanisms, and Clinical Implications

“…BMI was positively associated with basal TSH secretion in healthy individuals, but not with pulsatile or total TSH secretion, and a higher BMI was associated with a delay in the nocturnal onset of the TSH surge in 117 healthy subjects with a mean age of 43 (range 22–77) years and a mean BMI of 26.8 (range 18.3–39.4) kg/m 2 ( 23 ). In contrast, TSH levels were not different between a small group of overweight women ( N =22) and women with normal weight ( N =30) ( 75 ).…”

Association between thyroid hormones and skeletal muscle and bone in euthyroid type 2 diabetes patients

“… 35 However, other studies revealed no correlations between thyroid hormones and BMD in young euthyroid women. 36 Vendrami et al 37 found that TSH and FT4 had no correlations with BMD at any site in euthyroid postmenopausal women. This study showed no correlations of FT3, FT4, TSH, or FT3/FT4 with BMC and BMD of the lumbar spine and femur.…”