Association among age, height, weight, and body mass index with discordant regional bone mineral density

Causal Associations of Anthropometric Measurements With Fracture Risk and Bone Mineral Density: A Mendelian Randomization Study

Uncovering additional causal clinical traits and exposure variables is important when studying osteoporosis mechanisms and for the prevention of osteoporosis. Until recently, the causal relationship between anthropometric measurements and osteoporosis had not been fully revealed. In the present study, we utilized several state-of-the-art Mendelian randomization (MR) methods to investigate whether height, body mass index (BMI), waist-to-hip ratio (WHR), hip circumference (HC), and waist circumference (WC) are causally associated with two major characteristics of osteoporosis, bone mineral density (BMD) and fractures. Genomewide significant (p  ≤ 5 × 10^-8 ) single-nucleotide polymorphisms (SNPs) associated with the five anthropometric variables were obtained from previous large-scale genomewide association studies (GWAS) and were utilized as instrumental variables. Summary-level data of estimated bone mineral density (eBMD) and fractures were obtained from a large-scale UK Biobank GWAS. Of the MR methods utilized, the inverse-variance weighted method was the primary method used for analysis, and the weighted-median, MR-Egger, mode-based estimate, and MR pleiotropy residual sum and outlier methods were utilized for sensitivity analyses. The results of the present study indicated that each increase in height equal to a single standard deviation (SD) was associated with a 9.9% increase in risk of fracture (odds ratio [OR] = 1.099; 95% confidence interval [CI] 1.067-1.133; p = 8.793 × 10^-10 ) and a 0.080 SD decrease of estimated bone mineral density (95% CI -0.106-(-0.054); p = 2.322 × 10^-9 ). We also found that BMI was causally associated with eBMD (beta = 0.129, 95% CI 0.065-0.194; p = 8.113 × 10^-5 ) but not associated with fracture. The WHR adjusted for BMI, HC adjusted for BMI, and WC adjusted for BMI were not found to be related to fracture occurrence or eBMD. In conclusion, the present study provided genetic evidence for certain causal relationships between anthropometric measurements and bone mineral density or fracture risk. © 2021 American Society for Bone and Mineral Research (ASBMR).

Prevalence and factors of T-score discordance between hip and spine among middle-aged and elderly Malaysians

T-score discordance between hip and spine is a common problem in the diagnosis of osteoporosis based on dual-energy X-ray absorptiometry. Not much information on the prevalence and risk factors of this problem is available in Malaysia. Our study found that factors like age, height, physical activity and menopausal status should be taken into account in the diagnosis of osteoporosis.

INTRODUCTION AND OBJECTIVE

T-score discordance between hip and spine is a common problem in bone mineral density assessment. A difference ≥ 1 standard deviation (SD) (regardless of diagnostic class) is considered minor, and a difference more than one diagnostic class is considered major discordance. This study aimed to determine the prevalence and factors of hip and spine T-score discordance in a population aged ≥ 40 years in Klang Valley, Malaysia.

SUBJECTS AND METHODS

In this cross-sectional study, subjects answered a demographic questionnaire and underwent body composition and bone health assessment using dual-energy X-ray absorptiometry. Chi-square and binary logistic regression analysis were used to assess the prevalence of T-score discordance among the subjects.

RESULTS

A total of 786 Malaysians (382 men, 404 women) subjects were recruited. The prevalence of minor and major discordance was 30.3% and 2.3%, respectively. Overall, factors related to T-score discordance were advanced age, decreased height, and being physically active. Sub-analysis showed that decreased height and being physically active predicted T-score discordance in men, being menopausal and Indian (vs Chinese) were predictors in women.

CONCLUSIONS

T-score discordance between hip and spine is common among Malaysian middle-aged and elderly population. Diagnosis of osteopenia/osteoporosis should be based on the T-score of more than one skeletal site as per the current recommendations.

The impact of height on low/reduced bone mineral density in Chinese adolescents aged 12-14 years old: gender differences

Low/reduced bone mineral density (BMD) is an important predictor of childhood fracture. In this article, we presented the prevalence of BMD in Chinese adolescents and, for the first time, demonstrated the gender disparities in the impact of height on BMD.

PURPOSE

To analyze the gender disparities in the association of low/reduced BMD with height in Chinese adolescents at the stage of growth spurt.

METHODS

A total of 8152 adolescents aged 12-14 years old were included based on a cross-sectional study in Tianjin, China. Height and weight were measured with standard equipment. BMD was measured using the method of quantitative ultrasound. Adolescents with Z ≤ - 2.0 or - 2.0 < Z ≤ - 1.0 were defined as "low BMD" or "reduced BMD".

RESULTS

The total low/reduced BMD rate was 22.0% in Chinese adolescents aged 12-14 years old, and boys were more likely to have low/reduced BMD than girls (30.1% vs. 12.9%, P < 0.001). The rate of low/reduced BMD significantly increased with age in boys (P_trend = 0.019), whereas decreased with age in girls (P_trend = 0.018). We found significant interaction effect between gender and height standard deviation score (height-Z) in the association with low/reduced BMD (P_interaction < 0.001). There was a positive association of height-Z among boys (OR = 1.30, 95%CI 1.21-1.39, P < 0.001), meanwhile low/reduced BMD was inversely associated with height-Z among girls (OR = 0.85, 95%CI 0.78-0.94, P < 0.001).

CONCLUSIONS

Our study suggested strong gender disparities in the impact of height on BMD in Chinese adolescents aged 12-14 years old, where the association between low/reduced BMD and height was positive among boys but inverse among girls. The study provides evidence on the early prevention and the risk factor identification of low/reduced BMD and childhood fractures.

Opinions and attitudes concerning osteoporosis among Austrian general practitioners

General practitioners play a crucial role in the management of osteoporosis. Thus, it is essential to determine the opinions and attitudes of family doctors concerning this disease. A structured pencil-paper questionnaire was distributed to all general physicians in a practice in Austria and 3.2% responded. Results were compared with a similar survey carried out in 1993. 84.4% of the responding doctors regarded the public health impact of osteoporosis as rather or very important, compared with 49.2% in 1993. 83.3% regarded prevention of osteoporosis as effective or very effective. This proportion rose from 66.2% in 1993. Regular physical exercise was rated as most effective in the prevention of osteoporosis, followed by calcium-rich diet and vitamin D- and calcium supplementation. 33.6% reported carrying out a standardised risk assessment prior to referral/non-referral for bone mineral densitometry. The most frequently cited aspects of the patient's medical history leading to this examination were permanent corticosteroid therapy, a history of fractures, and pain, as reported by 93.6, 84.6 and 71.2%, respectively. The most frequently reported interventions recommended by doctors to their osteoporosis patients in the prevention of falls were reduction of trip hazards (87.2%), reduction of psychotropic drugs (50.0%), balance, strength and endurance training (57.7, 48.1, and 42.3%, respectively). These results reveal strengths in the approach to prevention and early recognition of osteoporosis and prevention of falls, but potential room for improvement in the management of osteoporosis by general practitioners is also shown.

Association of lower serum cholesterol levels with higher risk of osteoporosis in type 2 diabetes

OBJECTIVE

To determine whether a correlation exists between bone mineral density and circulating lipoprotein levels and whether these variables are independently associated with osteoporosis in patients with type 2 diabetes.

METHODS

In a cross-sectional analysis, 159 patients with type 2 diabetes were compared with 70 patients without diabetes selected from an outpatient endocrinology clinic in a tertiary care institute during a 1-year period. Variables were gathered through history, physical examination, and laboratory findings, including blood chemistry studies and dual-energy x-ray absorptiometry.

RESULTS

Of the 229 study patients, 86 (37.6%) had osteoporosis. In the patients with diabetes, the mean +/- SD of age, weight, total cholesterol, and low-density lipoprotein (LDL) cholesterol in those with and without osteoporosis was 72.3 +/- 10.4 years versus 63.6 +/- 11.0 years, 74.2 +/- 14.4 kg versus 83.7 +/- 15.5 kg, 178.4 +/- 33.7 mg/dL versus 194.1 +/- 33.9 mg/dL, and 100.0 +/- 27.1 mg/dL versus 114.2 +/- 30.2 mg/dL, respectively (P<0.01 for all variables). After adjustment for other variables, multiple logistic regression analysis showed that the presence of diabetes was associated with a lower risk of osteoporosis. Similarly, older age and lower body weight, LDL levels, and serum calcium levels were independently associated with lumbar spine osteoporosis in patients with diabetes, in comparison with older age and lower weight in patients without diabetes. Lower weight and older age were associated with femoral neck and total hip osteoporosis in patients with diabetes, in comparison with only older age in patients without diabetes.

CONCLUSION

The presence of type 2 diabetes is associated with a lower risk of osteoporosis. In patients with type 2 diabetes, a lower LDL level is more likely to be associated with osteoporosis at the lumbar spine.

The association between body mass index and osteoporosis in patients referred for a bone mineral density examination

PURPOSE

Osteoporosis affects 4-6 million (13%-18%) postmenopausal white women in the United States. Most studies to date on risk factors for osteoporosis have considered body mass index (BMI) only as a possible confounder. In this study, we assess the direct relationship between BMI and osteoporosis.

METHODS

We conducted a cross-sectional study among women aged 50-84 years referred by their physicians for a bone mineral density (BMD) examination at Baystate Medical Center between October 1998 and September 2000. BMI was determined prior to the BMD examination in the clinic. Information on other risk factors was obtained through a mailed questionnaire. Ordinal logistic regression was used to model the association between BMI and osteoporosis, controlling for confounding factors.

RESULTS

BMI was inversely associated with BMD status. After adjustment for age, prior hormone replacement therapy (HRT) use, and other factors, odds ratios (OR) for low, high, and obese compared with moderate BMI women were 1.8 (95% CI 1.2-2.7), 0.46 (95% CI 0.29- 0.71), and 0.22 (95% CI 0.14-0.36), respectively, with a significant linear trend (p < 0.0001) across BMI categories. Evaluating BMI as a continuous variable, the odds of bone loss decreased 12% for each unit increase in BMI (OR = 0.88, 95% CI 0.85-0.91).

CONCLUSIONS

Women with low BMI are at increased risk of osteoporosis. The change in risk associated with a 1 unit change in BMI ( approximately 5-8 lb) is of greater magnitude than most other modifiable risk factors. To help reduce the risk of osteoporosis, patients should be advised to maintain a normal weight.

Genetic and environmental correlations between bone phenotypes and anthropometric indices in Chinese

Height, weight, bone mineral density (BMD), and bone size are all influenced by genetic and environmental factors as well as interactions between them. Height and weight are often used in population studies to adjust the bone phenotypes. However, it is still unknown what proportion of genetic and environmental variability is shared between these anthropometric characteristics and the bone phenotypes. The genetic and environmental correlations between the bone phenotypes and anthropometric indices in Chinese subjects were studied by bivariate quantitative genetic analysis on a sample of 931 healthy subjects from 292 Chinese nuclear families aged from 19 to 79 years. BMD and bone size at the lumbar spine (L1-L4) and the hip of all subjects were measured by dual-energy X-ray absorptiometry. We found significant genetic correlations between weight and spine BMD, hip BMD, spine bone size and hip bone size, which were 0.50 (P<0.01), 0.45 (P<0.01), 0.36 (P=0.02), and 0.38 (P<0.01), respectively. Likewise, significant genetic correlations between height and spine BMD, spine bone size, and hip bone size were 0.30 (P=0.02), 0.54 (P<0.01), and 0.58 (P<0.01), respectively. The environmental correlations were found to be significant only between height and spine bone size (P<0.001) and weight and hip BMD (P=0.02). These results suggest the probability that the same genetic and environmental factors contribute to these different phenotypes. Moreover, when a candidate gene or genomic region is responsible for the variation of both bone phenotypes and anthropometric indices, its true genetic effect on the bone phenotypes may be lost after one has adjusted the phenotypic values with weight and height as random environmental factors. It may have implications for population studies of candidate genes that underlie the complex bone phenotypes and for the development of strategies for therapeutic application.

Radioanatomical measurements of the medullary cavity of the humerus in Kuwait: ethnic differences and clinical implications for fracture fixation

OBJECTIVE

To compare the difference in diameter of the medullary cavity of the humerus in Arab and South Asian patients in Kuwait.

SUBJECTS AND METHODS

In 46 patients (29 Arab, 17 South Asian) treated at Al-Razi Hospital, Kuwait, for diaphyseal fracture of the humerus, the medullary cavity of the humerus on the radiographs of the uninjured (contralateral side) was examined. Bone density was also measured. Statistical significance was calculated by parametric and nonparametric test using SPSS package.

RESULTS

South Asians had a significantly narrower medullary cavity (p < 0.05) and higher cortical indices (p < 0.05) than Arabs, and also a narrower external diameter of the humerus at levels 5 and 6 (p < 0.05).

CONCLUSION

In cases of fracture of the humerus, radiographic measurements of the diameter of the medullary cavity of the uninjured side were essential in selecting the appropriate fixation device.