Correction to: Differences in bone quality and strength between Asian and Caucasian young men.

The second name of the ninth author, X.E. Guo, was incorrectly coded as part of his surname. The publisher apologises for the inconvenience caused.

Differences in bone quality and strength between Asian and Caucasian young men.

This is a cross-sectional study to assess differences in bone quality in young Asian and Caucasian (n = 30/group) men between 25 and 35 years. We found that Asians had smaller bones, thicker and denser cortices, and more plate-like trabeculae, but stiffness did not differ between groups. INTRODUCTION: We conducted a cross-sectional study to assess differences in bone quality in young Asian and Caucasian (n = 30/group) men between 25 and 35 years. METHODS: We measured bone mineral density (BMD) at the spine, total hip (TH), femoral neck (FN), and forearm by dual energy X-ray absorptiometry (DXA), and bone geometry, density, microarchitecture, and mechanical competence at the radius and tibia by high-resolution peripheral quantitative computed tomography (HR-pQCT) with application of individual trabecula segmentation (ITS) and trabecular and whole bone finite element analysis (FEA). We measured load-to-strength ratio to account for differences in bone size and height, respectively. We used Wilcoxon rank sum and generalized linear models adjusted for height, weight, and their interaction for comparisons. RESULTS: Asians were 3.9 % shorter and weighed 6.5 % less than Caucasians. In adjusted models: by DXA, there were no significant race-based differences in areal BMD; by HR-pQCT, at the radius, Asians had smaller total and trabecular area (p = 0.003 for both), and denser (p = 0.01) and thicker (p = 0.04) cortices at the radius; by ITS, at the radius Asians, had more plate-like than rod-like trabeculae (PR ratio p = 0.01), greater plate trabecular surface (p = 0.009) and longer rod length (p = 0.002). There were no significant race-based differences in FEA or the load-to-strength ratio. CONCLUSIONS: Asians had smaller bones, thicker and denser cortices, and more plate-like trabeculae, but biomechanical estimates of bone strength did not differ between groups. Studies are needed to determine whether these differences persist later in life.

Development of morphologically dominant follicles is associated with fewer metabolic disturbances in amenorrheic women with polycystic ovary syndrome: a pilot study.

OBJECTIVES: To determine if amenorrheic women with polycystic ovary syndrome (PCOS) demonstrate ultrasonographically detectable changes in follicle population. METHODS: Sixteen women with PCOS reporting the absence of menses for more than 3 months were enrolled in the study. Subjects had a physical examination, fasting blood tests and two transvaginal ultrasound scans spaced 1 month apart. In cases where evidence of a morphologically dominant follicle (≥ 10 mm in diameter) occurred, subsequent ultrasound scans were performed to determine the fate of the dominant follicle. Differences in total follicle population, maximum follicle diameter and clinical, hormonal and metabolic features were determined. RESULTS: Forty-four percent of subjects showed changes in follicle population of 6-10 follicles and 37% showed changes in follicle population of > 10. Maximum follicle diameters ranged between 5.4 and 33.0 mm. Four subjects demonstrated follicle diameters ≥ 10 mm. Of those who developed dominant follicles, two subjects ovulated, one subject developed a persistent anovulatory follicle and the dominant follicle regressed in the remaining subject. Diagnostic criteria for PCOS were similar among women that did or did not develop dominant follicles (menstrual cycle length, P = 0.880; hirsutism score, P = 0.809; free androgen index, P = 0.991; total follicle count, P = 0.199). However, lower glycosylated hemoglobin (P = 0.047) and insulin levels (P = 0.049) and better insulin sensitivity (P = 0.048) were noted in women who attained dominant follicles. CONCLUSION: Amenorrheic women with PCOS demonstrate changes in follicle population that are consistent with active follicle growth and regression despite prolonged periods of anovulation. Morphologic selection occurs in amenorrheic women and attainment of dominant follicles is associated with improved metabolic status.