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Biomedical subjects

Xiping Xu

Publications and source records attributed to Xiping Xu.

At least 19 recordsLinked to original sources
PubMed2007

CYP19A1 polymorphisms are associated with bone mineral density in Chinese men.

Aromatase-dependent biosynthesis of estrogen plays an important role in maintenance of the male skeleton, and Cytochrome p450 aromatase is the key enzyme to catalyze the conversion of androgen precursors to estrogens. We investigated the association of polymorphisms in the CYP19A1 gene and bone mineral density in a Chinese cohort. 2392 extreme low femoral neck BMD cases or extreme high femoral neck BMD controls were selected from a population-based cohort and genotyped for eight SNPs in the CYP19A1 gene. Significant associations for rs17703883, rs12594287 and rs16964201 SNPs with BMD were found in men only. Men with TC/CC genotypes in the rs17703883 SNP had a 1.5 times higher risk of having extreme low femoral neck BMD (P = 0.003, empirical P value = 0.05), and decreased BMDs at total body (P = 0.004, empirical P value = 0.07) and total hip (P = 0.003, empirical P value = 0.05). Men carrying AA/AG genotypes in the rs12594287 SNP had a 30% reduced risk of having extreme low femoral neck BMD (P = 0.007, empirical P value = 0.12), and increased BMDs at total body (P = 0.0009, empirical P value = 0.018) and total hip (P = 0.001, empirical P value = 0.02). Men carrying TT/TC genotypes in the rs16964201 SNP had a 40% reduced risk of having extreme low femoral neck BMD (P = 0.005, empirical P value = 0.087), and increased BMDs at total body (P = 0.0001, empirical P value = 0.002) and total hip (P = 0.0006, empirical P value = 0.012). Haplotype analysis showed that the G-C-T-A-T haplotype was significantly related to higher BMD. Our finding suggests that genetic variations in the CYP19A1 gene are significantly associated with BMD at different skeletal sites in adult men, but not in women.

Adult↗
PubMed2007

Large-scale genome-wide linkage analysis for loci linked to BMD at different skeletal sites in extreme selected sibships.

UNLABELLED: Few genome-wide linkage studies of osteoporosis have been conducted in the Asian population. We performed a genome-wide scan involving 3093 adult siblings with at least one sib-pair extremely concordant or discordant for hip BMD. Our results indicated four genome-wide significant QTLs for BMD. In comparison with 12 previous reported linkage studies, we reveal novel linkage regions that have reaching global significance. INTRODUCTION: The genetic basis for osteoporosis has been firmly established, but efforts to identify genes associated with this complex trait have been incomplete, especially in Asian populations. The purpose of this study was to identify quantitative trait loci (QTLs) for BMD in a Chinese population. MATERIALS AND METHODS: We performed a genome-wide scan involving 3093 siblings 25-64 years of age from 941 families, with at least one sib-pair extreme concordant or discordant for total hip BMD from a large community-based cohort (n = 23,327) in Anhui, China. Linkage analysis was performed on BMD residuals adjusted for age, height, weight, occupation, cigarette smoking, physical activity, and alcohol consumption using the revised Haseman-Elston regression-based linkage model. RESULTS: Our results revealed significant QTLs on chromosome 7p21.2 for femoral neck BMD (LOD = 3.68) and on chromosome 2q24.3 for total hip BMD (LOD = 3.65). Suggestive linkage regions were found to overlap among different skeletal sites on chromosomes 2q, 7p, and 16q. Sex-specific linkage analysis further revealed a significant QTL for lumbar spine BMD on chromosome 13q21.1 (LOD = 3.62) in women only. When performing multivariate linkage analysis by combining BMDs at four skeletal sites (i.e., whole body, total hip, femoral neck, and lumbar spine BMD), an additional significant QTL was found at chromosome 5q21.2 (LOD = 4.56). None of these significant QTLs found in our study overlapped with major QTLs reported by other studies. CONCLUSIONS: This study reveals four novel QTLs in a Chinese population and suggests that BMD at different skeletal sites may also share common genetic determinants.

Asian People↗
PubMed2006

Association of the methylenetetrahydrofolate reductase C677T polymorphism and fracture risk in Chinese postmenopausal women.

Osteoporotic fractures are a leading cause of disability and, indirectly, of death in the elderly population. Previous studies have shown that homocysteine level and the C677T polymorphism in the gene encoding methylenetetrahydrofolate reductase (MTHFR) may be involved in the development of osteoporosis and its related fracture in European populations. The aim of this study was to verify the association of this polymorphism with bone mineral density (BMD) and fractures in our 1899 Chinese postmenopausal women. The C677T T allele frequency in this population was 39.2%. The distribution of the MTHFR genotypes followed the Hardy-Weinberg equilibrium. BMD at total body, total hip or femoral neck did not significantly vary with MTHFR C677T genotype. The T allele carrier tended to have higher risk of having osteoporosis or osteopenia, but the difference was statistically insignificant. However, Poisson regression analysis revealed that the T allele carriers had an increased risk of fractures (RR=1.7, 95% CI=1.1-2.7, p=0.01) which occurred before or after menopause. As far as fracture incidence after menopause was concerned, the CT or TT genotype had more than twice the risk of the CC genotype (RR=2.5, 95% CI=1.2-4.9, p=0.009). This association was independent of age, physical activity, occupation, passive smoking, height, weight, years since menopause, and total hip BMD. Our data show that the MTHFR C677T polymorphism is an independent predictor of fracture risk, although it only had a weak effect on BMD. Further study on the mechanistic role that this polymorphism plays in the development of fractures may lead to better understanding of the etiology of osteoporotic fracture.

Absorptiometry, Photon↗
PubMed2006

Prevalence and physical determinants of low back pain in a rural Chinese population.

STUDY DESIGN: This was a community-based cross-sectional study that is part of an ongoing study of genetics and osteoporosis. OBJECTIVES: To estimate the 1-year self-reported prevalence of low back pain (LBP); and to assess the association between physical exposures (occupation, physical stress, and vibration) and LBP in a rural Chinese population. This study also explored how these associations change when individuals with LBP report additional pains in other parts of the body. SUMMARY OF BACKGROUND DATA: Little is known about the prevalence and determinants of LBP in rural developing populations, even though approximately half of the world's population, mostly from the developing world, is engaged in agriculture, a known strenuous activity. METHODS: Families with at least three participating siblings residing in the surrounding rural region of Anqing city, Anhui Province, China, were invited to participate in the study through public announcements and direct invitations by village physicians. A questionnaire including demographics, physical exposures, and musculoskeletal pain was administered to 13,965 men and women (age, 25-64 years). Generalized estimating equations were used to estimate LBP prevalence and examine associations between LBP and physical exposures. RESULTS: The 1-year prevalence of LBP was 64%. Twenty-five percent reported no pain at any body site. Women had higher prevalence of LBP than men across all age groups. Being a farmer, reporting moderate or heavy physical stress, and having had former or current exposures to vibration were positively associated with LBP (P < 0.05). Physical exposures were also associated with cases of LBP combined with other musculoskeletal pains, and generally, the more pains individuals reported, the more likely it was that they were farmers and were exposed to vibration. CONCLUSION: A high prevalence of LBP and LBP with additional musculoskeletal pain existed in this rural Chinese sample. We found evidence of a link between physical exposures and LBP, and LBP with additional musculoskeletal pain. Further understanding of the characteristics and risk factors of LBP in rural developing areas is needed.

Adult↗
PubMed2006

A prospective study of serum DDT and progesterone and estrogen levels across the menstrual cycle in nulliparous women of reproductive age.

The authors explored whether exposure to 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) and its isomers and metabolites affects female reproductive hormones characterized by urinary pregnanediol-3-glucuronide (PdG) and estrone conjugate (E(1)C) levels. During 1996-1998, 287 newly married Chinese women nonsmokers intending to conceive were prospectively studied. Serum for DDT measurement was collected at enrollment, and daily menstrual diaries and urine specimens were collected for 1 year or until a clinical pregnancy was achieved. More than 500 menstrual cycles were studied totaling over 8,000 days. Day of ovulation was determined for each cycle, and the association of serum DDT levels with daily PdG and E(1)C levels in a +/-10-day window around ovulation was analyzed. After adjustment for covariates including age, body mass index, and occupational exposures, consistent inverse associations of most DDT forms occurred with urine E(1)C during the periovulation phase and with urine PdG during the luteal phase of the menstrual cycle. For example, a 10-ng/g increase in serum p,p'-DDE was associated with a 0.05-log(E(1)C) decrease (p = 0.03) in the periovulation phase and a 0.06-log(PdG) decrease (p = 0.03) in the luteal phase. These results support the potential for DDT to be associated with decrements in estrogen and progesterone levels at times during the menstrual cycle that are critical for ovulation and early pregnancy maintenance.

Adult↗
PubMed2006

Environmental pyrethroid and organophosphorus insecticide exposures and sperm concentration.

BACKGROUND: There is growing concern that poisoning and other adverse health effects are increasing because organophosphorous (OP) insecticides are now being used in combination with pyrethroid (PYR) insecticides to enhance the toxic effects of PYR insecticides on target insects, especially those that have developed PYR resistance. OBJECTIVES: We conducted a pilot biomonitoring study to determine whether men in our reproductive cohort study were being exposed to pesticides environmentally by virtue of frequenting an agricultural setting. METHODS: We screened 18 randomly selected urine samples collected from male participants of reproductive age for 24 parent compounds and metabolites of pesticides and examined the results in relation to sperm concentration. RESULTS: Results showed high prevalence of exposure to OP and PYR pesticides and our preliminary analyses provided some suggestion that the higher exposure group had lower sperm concentration. CONCLUSIONS: The potential of OP/PYR mixtures to have enhanced human toxicity needs more research attention.

Adult↗
PubMed2006

Impact of seafood and fruit consumption on bone mineral density.

OBJECTIVES: Over the past decade, dietary choices and nutrition have proven to be major modulators of bone mineral density (BMD) in men and women. We investigated environmental determinants, specifically dietary habits, of BMD by using multiple regression models in a rural Chinese population. METHODS: BMDs were measured at the hip and total body in 5848 men and 6207 women, aged 25-64. Dietary and supplemental intakes were assessed by a simple, one-page questionnaire tailored to collect nutritional information from large rural populations. Another questionnaire was used to collect information on the subjects' age, disease history, smoking, alcohol consumption, physical activity as well as women's menstrual status and reproductive history. Multiple regression models were used to assess the relationships among dietary variables and BMD, after adjusting for age, BMI (body mass index), weight, occupation, smoking status, and alcohol consumption. RESULTS: Increasing seafood consumption was significantly associated with greater BMD in women (p<0.001), especially those consuming more than 250 g per week of seafood. One thousand and three hundred and twenty-four men and 1479 women consumed >250 g of fruit per week. Higher fruit intake was found to be significantly associated with higher BMD in both sexes (p<0.05). High vegetable consumption, however, did not positively impact BMD. CONCLUSIONS: This study with its large population size has identified preventive measures, as well as some risk factors, involved in bone loss and osteoporosis. Our results highlight the importance of several dietary variables as significant determinants of BMD. It also emphasizes the role of dietary intake in general and shows that specific foods, such as fruits and seafood, can positively impact BMD.

Absorptiometry, Photon↗
PubMed2006

Urinary estrogen and progesterone metabolite concentrations in menstrual cycles of fertile women with non-conception, early pregnancy loss or clinical pregnancy.

BACKGROUND: Knowledge is limited of how estrogen and progesterone variability in fertile women are associated with achieving pregnancy. METHODS: From 1996 to 1998, we enrolled 347 textile workers without hormone treatment in Anhui, China, who provided daily urine and data upon stopping contraception for up to 1 year until clinical pregnancy. Urinary hCG was assayed to detect conception and early pregnancy losses. We compared urinary concentrations of estrone conjugates (E(1)C) and pregnanediol-3-glucuronide (PdG) in 266 clinical pregnancies, 63 early pregnancy losses and 272 non-conception cycles from 347 women and also in 94 clinical pregnancy and 94 non-conception cycles from the same women. RESULTS: Using generalized estimating equations and relative to 266 clinical pregnancy cycles, log(E(1)C) was lower in 272 non-conception cycles [beta = -0.3 ng/mg creatinine (Cr); SE = 0.1; P < 0.0001]. On average, daily E(1)C was 18 ng/mg Cr lower in non-conception cycles than in clinical pregnancy cycles. Relative to 94 clinical pregnancy cycles, log(E(1)C) was lower in 94 non-conception cycles (beta = -0.4 ng/mg Cr; SE = 0.1; P < 0.0001) from the same women (average difference in daily E(1)C was 20 ng/mg Cr). The odds of E(1)C less than the 10th percentile (<30 ng/mg Cr) were higher in early pregnancy loss cycles [odds ratio (OR) = 4.8; P = 0.0027] than in clinical pregnancy cycles in the early luteal phase. Compared with clinical pregnancy cycles, log(PdG) concentrations were lower in non-conception cycles during the follicular phase, but this analysis lacked power for multiple testing. CONCLUSIONS: Estrogen concentrations varied from cycle to cycle, and higher estrogen was associated with achieving clinical pregnancy.

Abortion, Spontaneous↗
PubMed2006

Prolylcarboxypeptidase gene, chronic hypertension, and risk of preeclampsia.

OBJECTIVE: Renin-angiotensin System is essential for the homeostasis of blood pressure in humans. The roles of renin-angiotensin system gene polymorphisms including angiotensinogen, angiotensin-converting enzyme, renin and angiotensin II receptor, type 1 genes in the pathogenesis of preeclampsia have been extensively studied, but most association studies produced either negative or inconsistent results. Prolylcarboxypeptidase encodes a lysosomal enzyme and is a regulator for both renin-angiotensin system and the kallikrein-kinin system. There is no published study on prolylcarboxypeptidase gene and preeclampsia. STUDY DESIGN: We investigated the independent and joint association of five polymorphisms in angiotensinogen, angiotensin-converting enzyme, and prolylcarboxypeptidase gene and chronic hypertension with the risk of preeclampsia in 125 preeclamptic and 1040 non-preeclamptic black women enrolled at the Boston Medical Center. We used logistic regression models to estimate the odds ratios of risk for preeclampsia associated with each gene polymorphism and its joint association with chronic hypertension. RESULTS: No association was found in four polymorphisms in angiotensinogen and angiotensin-converting enzyme. Prolylcarboxypeptidase E112D (rs2298668) D allele along and jointly with chronic hypertension were associated with a significantly increased risk of preeclampsia. Compared to women with homozygous EE genotype and without chronic hypertension, higher risks of preeclampsia were observed in DD women without chronic hypertension (OR = 3.7, 95% CI, 1.2 - 12.4) and EE women with chronic hypertension (OR = 9.1, 95% CI: 4.7 - 17.6). Women with both D allele and chronic hypertension had the highest risk (OR = 158, 95% CI, 25-infinite). This finding was validated in an independent sample of 1,015 non-black women. We further compared the prolylcarboxypeptidase transcript levels in peripheral blood cells of 23 preeclamptic (30% with chronic hypertension) and 51 non-preeclamptic (6% with chronic hypertension) women 2 - 3 days after delivery. The PRCP transcript levels were lower in ED/DD women than in EE woman (P = .03) and lower in preeclamptic women than in non-preeclamptic women (P = .007). CONCLUSION: Our data showed that prolylcarboxypeptidase D allele coupled with chronic hypertension was associated with a significantly increased risk of preeclampsia in both black and non-black women. Gene expression assays lent further support for the functional significance of prolylcarboxypeptidase in the etiology of preeclampsia.

Adult↗
PubMed2006

Daily immunoactive and bioactive human chorionic gonadotropin profiles in periimplantation urine samples.

A need exists for broadly applicable biomarkers of pregnancy outcome in population-based studies that assess environmental hazards to human reproduction. Previous studies have demonstrated that during the periimplantation period, measures of the circulating levels of immunoreactive hCG (IhCG) are not predictive of pregnancy outcome, whereas measurements of the circulating levels of bioactive hCG (BhCG) provide information relating to pregnancy outcome and might provide the basis for an early biomarker of pregnancy outcome. However, for this biomarker to have broad application in population-based studies, it must be adapted to urinary hCG metabolites. The principle objective of the present study was to characterize the periimplantation excretion patterns of urinary hCG metabolites of pregnancies that resulted in live birth (LB), early pregnancy loss (EPL), and recognized clinical abortion (CAB) with an immunoenzymometric assay specific to intact hCG and an LH/chorionic gonadotropin cellular bioassay as the basis for a preliminary comparison between successful (LB) and failing (EPL and CAB) outcome groups. Automated immunoassays for FSH and hCG were used to define each conceptive cycle's implantation window. The timing of first hCG detection was significantly later for the EPL group. Pregnancies that resulted in LB had consistently rising average daily IhCG and BhCG levels, with no significant differences when average daily IhCG and BhCG measurements were compared (Student t-test, P>0.05), whereas pregnancies that resulted in CAB and EFL had lower average daily IhCG and BhCG levels that increased inconsistently. These findings demonstrate that critical information related to pregnancy outcome may be present when multiple urinary hCG isoforms are measured. Further data suggest that the rate of change for the ratio of daily BhCG over IhCG levels might be useful as the basis of a broadly applicable early biomarker for pregnancy outcome.

Abortion, Spontaneous↗
PubMed2006

G protein-coupled receptor 154 gene polymorphism is associated with airway hyperresponsiveness to methacholine in a Chinese population.

BACKGROUND: A new asthma susceptibility gene, the G protein-coupled receptor for asthma susceptibility (GPRA, GPR154), has recently been identified and the association was replicated in 2 white populations, but not in a Korean population. OBJECTIVE: To test the association between GPR154 gene polymorphisms and airway responsiveness to methacholine in a Chinese population. METHODS: Eight single nucleotide polymorphisms (SNPs) in the GPR154 gene were genotyped in 451 cases and 232 controls in stage I. The association of 1 SNP, rs324981, was tested in an additional 264 case and 241 control subjects in stage II. Both single marker and haplotype associations were tested. RESULTS: In stage I, we found that airway hyperresponsiveness to methacholine was associated with 2 single SNPs, rs324981 and rs324987, but not with the haplotypes of GPR154. The minor allele homozygotes of rs324981 (AA) and rs324987 (TT) were at a significantly lower risk of hyperresponsiveness to methacholine with odds ratios of 0.59 (P=.02) and 0.56 (P=.01), respectively. In stage II, we found a similar trend of association between rs324981 and airway hyperresponsiveness (P=.09). In the pooled analysis, the odds ratio of the AA homozygote of rs324981 was 0.61 (P=.004). The permutation test resulted in a study-wide empirical P value of .023, which meant that the association remained significant after adjustment for multiple tests. CONCLUSIONS: Our study supports a role of the GPR154 gene in asthma susceptibility and suggests that the AA homozygote of rs324981 is a protective factor for airway hyperresponsiveness to methacholine in a Chinese population. CLINICAL IMPLICATIONS: Our findings confirmed a role of GPR154 in the genetic susceptibility of asthma and suggest that GPR154 polymorphism should be taken into consideration to improve the assessment of an individual's risk of asthma.

Adolescent↗
PubMed2006

An efficient family-based association test using multiple markers.

In genetic association studies, multiple markers are usually employed to cover a genomic region of interest for localizing a trait locus. In this report, we propose a novel multi-marker family-based association test (T(LC)) that linearly combines the single-marker test statistics using data-driven weights. We examine the type-I error rate in a numerical study and compare its power to identify a common trait locus using tag single nucleotide polymorphisms (SNPs) within the same haplotype block that the trait locus resides with three competing tests including a global haplotype test (T(H)), a multi-marker test similar to the Hotelling-T(2) test for the population-based data (T(MM)), and a single-marker test with Bonferroni's correction for multiple testing (T(B)). The type-I error rate of T(LC) is well maintained in our numeric study. In all the scenarios we examined, T(LC) is the most powerful, followed by T(B). T(MM) and T(H) are the poorest. T(H) and T(MM) have essentially the same power when parents are available. However, when both parents are missing, T(MM) is substantially more powerful than T(H). We also apply this new test on a data set from a previous association study on nicotine dependence.

Family↗
PubMed2006

Bronchodilator responses in Chinese children from asthma index families and the general population.

BACKGROUND: Although airway hyperresponsiveness to bronchoconstrictors has been extensively investigated, epidemiologic studies on airway hyperresponsiveness to bronchodilators are limited. OBJECTIVE: Our goal was to characterize the distribution and determinants of bronchodilator response (BDR) and bronchodilator hyperresponsiveness (BDHR) in rural Chinese children age 8 to 15 years. METHODS: Our study included children with and without asthma from asthma index families (1131 boys, 1143 girls) and subjects without asthma from general population controls (457 boys, 377 girls). BDR was calculated as [(post bronchodilator FEV1- baseline FEV1)/baseline FEV1] x 100. BDHR was defined as BDR greater than 12%. We investigated the distributions and major determinants of BDR and BDHR using scatterplots and multiple linear and logistic regression models. RESULTS: There was a gradient in BDR by asthma status and family history. The mean (+/-SD) BDR was 7% +/- 9% in subjects with asthma, 4% +/- 5% in subjects without asthma from index families, and 3% +/- 5% in controls. This trend was also seen for BHDR. BDR generally decreased with age. There was a notable sex difference in BDR around puberty in subjects with asthma. Sex difference was also seen in the relationship of BDR with body mass index. Additional variables correlated with BDR included height and prebronchodilator FEV1. Atopy was not correlated with BDR. In models accounting for these variables, chronic respiratory symptoms were associated with BDR and BDHR. CONCLUSION: In these Chinese children, multiple factors affected BDR, including age, sex, height, body mass index, asthma status, and family history of asthma. CLINICAL IMPLICATIONS: Because BDR can be affected by multiple factors, interpretation of clinical or research findings on BDR needs to take these factors into consideration.

Adolescent↗
PubMed2006

Prevalence of metabolic syndrome and its relation to body composition in a Chinese rural population.

OBJECTIVE: To investigate the prevalence of metabolic syndrome (MetS) with three different working definitions in a rural Chinese population and to examine its relation to body composition. RESEARCH METHODS AND PROCEDURES: A total of 18,630 adults 25 to 64 years old (mean age, 45.8 years; 51.2% men) from 5686 families were enrolled from Anhui province of China during 2004 to 2005. Anthropometric measurement, body composition, blood pressure, plasma lipids, and fasting glucose and insulin and a questionnaire-based interview were obtained from each participant. Three different working definitions for MetS, including the U.S. National Cholesterol Education Program's Adult Treatment Panel III, a modified Adult Treatment Panel III that adopts the World Health Organization's criterion for central obesity in Asian populations, and one recently proposed by the International Diabetes Federation, were used in the study. RESULTS: According to the three definitions, the age-adjusted prevalence of MetS for adults 25 to 64 years old was 3.2%, 4.9%, and 3.9% in men and 7.2%, 11.5%, and 10.9% in women, respectively. MetS prevalence increases significantly with age in women, but not in men. Body fat percentage and BMI and waist circumference were significantly associated with each component of MetS, especially with triglyceride level, insulin resistance index, and number of MetS components (r = 0.28 to 0.49). DISCUSSION: The age-adjusted prevalence of MetS in our study population is lower than that reported in other urban Chinese populations. Significant gender differences in MetS prevalence were observed. The waist circumference is a good surrogate for abdominal fat percentage.

Abdominal Fat↗
PubMed2006

Relation of body composition, fat mass, and serum lipids to osteoporotic fractures and bone mineral density in Chinese men and women.

BACKGROUND: Higher fat mass may be an independent risk factor for osteoporosis and osteoporotic fractures. OBJECTIVE: We aimed to determine the independent contribution of fat mass to osteoporosis and to estimate the risk of osteoporotic fractures in relation to body weight, lean mass, and other confounders. DESIGN: This was a community-based, cross-sectional study of 7137 men, 4585 premenopausal women, and 2248 postmenopausal women aged 25-64 y. Total-body and hip bone mineral content (BMC) and bone mineral density (BMD) and body composition were measured by dual-energy X-ray absorptiometry. Serum lipids were measured. Sex- and menopause-specific multiple generalized linear models were applied. RESULTS: Across 5-kg strata of body weight, fat mass was significantly inversely associated with BMC in the whole body and total hip. When we compared the highest quartile with the lowest quartile of percentage fat mass in men, premenopausal women, and postmenopausal women, the adjusted odds ratios (95% CIs) of osteoporosis defined by hip BMD were 5.2 (2.1, 13.2), 5.0 (1.7, 15.1), and 6.9 (4.3, 11.2), respectively. Significant linear trends existed for higher risks of osteoporosis, osteopenia, and nonspine fractures with higher percentage fat mass. Significant negative relations were found between whole-body BMC and cholesterol, triacylglycerol, LDL, and the ratio of HDL to LDL in all groups. CONCLUSIONS: Risks of osteoporosis, osteopenia, and nonspine fractures were significantly higher for subjects with higher percentage body fat independent of body weight, physical activity, and age. Thus, fat mass has a negative effect on bone mass in contrast with the positive effect of weight-bearing itself.

Absorptiometry, Photon↗
PubMed2005

Heart rate-corrected QT interval duration is significantly associated with blood pressure in Chinese hypertensives.

INTRODUCTION: Many studies demonstrated that a prolonged heart rate-corrected QT interval (QTc) increases the risk of malignant ventricular arrhythmias and sudden death. METHODS: We measured the electrocardiogram and blood pressure of 1480 hypertensive patients and assessed the relationship between the length of QTc and blood pressure. RESULTS: The mean QTc is longer in female than in male participants. There was a positive association between QTc and blood pressure in both men and women. The estimated increase in systolic and diastolic blood pressure for each 100-millisecond increase in QTc was 6.4 and 5.0 mm Hg in men and 3.7 and 2.5 mm Hg in women, respectively. CONCLUSION: Our study demonstrated a significant positive relationship between the QTc interval and baseline blood pressure in a Chinese hypertensive population.

Adult↗