Serum C reactive protein levels and genetic variation in the CRP gene are not associated with the prevalence, incidence or progression of osteoarthritis independent of body mass index.

OBJECTIVE: To study the relationship between serum C reactive protein (CRP) levels, genetic variation in the CRP gene and the prevalence, incidence and progression of radiographic osteoarthritis (ROA) in the Rotterdam Study-I (RS-I). A systematic review of studies assessing the relationship between osteoarthritis (OA) and CRP levels was also performed. METHODS: The association between CRP levels and genetic variation in the CRP gene and ROA was examined in 861 patients with hand OA, 718 with knee OA, 349 with hip OA and 2806 controls in the RS-I using one-way analysis of covariance and logistic regression, respectively. PubMed was searched for articles published between January 1992 and August 2009 assessing the relationship between CRP levels and OA. RESULTS: In RS-I the prevalence of knee OA, but not hip OA or hand OA, was associated with 14% higher serum CRP levels compared with controls (p=0.001). This association disappeared after adjustment for age and especially body mass index (BMI) (p=0.33). Genetic variation of the CRP gene was not consistently associated with the prevalence, incidence or progression of OA within RS-I. The systematic review included 18 studies (including RS-I) on serum CRP levels and the prevalence, incidence or progression of OA. Consistently higher crude CRP levels were found in cases of prevalent knee OA compared with controls. No association was observed between serum CRP levels and the prevalence of knee OA following adjustment for BMI (n=3 studies, meta-analysis p value=0.61). CONCLUSION: There is no evidence of association between serum CRP levels or genetic variation in the CRP gene with the prevalence, incidence or progression of OA independent of BMI.

Heritability of blood pressure traits and the genetic contribution to blood pressure variance explained by four blood-pressure-related genes.

OBJECTIVE: To study the heritability of four blood pressure traits and the proportion of variance explained by four blood-pressure-related genes. METHODS: All participants are members of an extended pedigree from a Dutch genetically isolated population. Heritability and genetic correlations of systolic blood pressure, diastolic blood pressure, mean arterial pressure and pulse pressure were assessed using a variance components approach (SOLAR). Polymorphisms of the alpha-adducin (ADD1), angiotensinogen (AGT), angiotensin II type 1 receptor (AT1R) and G protein beta3 (GNB3) genes were typed. RESULTS: Heritability estimates were significant for all four blood pressure traits, ranging between 0.24 and 0.37. Genetic correlations between systolic blood pressure, diastolic blood pressure and mean arterial pressure were high (0.93-0.98), and those between pulse pressure and diastolic blood pressure were low (0.05). The ADD1 polymorphism explained 0.3% of the variance of pulse pressure (P = 0.07), and the polymorphism of GNB3 explained 0.4% of the variance of systolic blood pressure (P = 0.02), 0.2% of mean arterial pressure (P = 0.05) and 0.3% of pulse pressure (P = 0.06). CONCLUSION: Genetic factors contribute to a substantial proportion of blood pressure variance. In this study, the effect of polymorphisms of ADD1, AGT, AT1R and GNB3 explained a very small proportion of the heritability of blood pressure traits. As new genes associated with blood pressure are localized in the future, their effect on blood pressure variance should be calculated.

Vitamin D receptor gene BsmI and TaqI polymorphisms and fracture risk: a meta-analysis.

INTRODUCTION: Fracture is the major clinical outcome of osteoporosis. The vitamin D receptor (VDR) gene is thought to be a candidate gene for osteoporosis. Many genetic studies have suggested an association of VDR polymorphisms and osteoporosis, but evidence remains conflicting. MATERIALS AND METHODS: We searched published studies from 1996 to September 2005 through PubMed and evaluated the genetic effect of the BsmI and TaqI polymorphism of VDR on fracture risk in a meta-analysis. Thirteen studies with a total of 20 eligible comparisons (1632 fracture cases and 5203 controls) were analyzed with fixed and random effects models. RESULT: No evidence of relationship between the VDR BsmI or TaqI polymorphism and fracture risk was observed with any genetic model. The odds ratio (95% confidence interval) of b-allele versus B-allele was 0.98 (0.86-1.12) with random effects calculations. There was significant between-study heterogeneity. Small studies did not differ significantly from larger ones. CONCLUSION: No relationship of the VDR BsmI or TaqI polymorphism and fracture risk was found in the meta-analysis of published data.

High pretransplant parathyroid hormone levels increase the risk for graft failure after renal transplantation.

BACKGROUND: Calcium (Ca), phosphate (P), and parathyroid hormone (PTH) are important variables influencing the risk for cardiovascular disease in dialysis patients. We studied the influence of long-standing Ca-P disregulation on renal transplant survival. METHODS: Pretransplant PTH, Ca, P, total protein (TP), albumin, and alkaline phosphatase (AP) values were gathered in all 407 patients that received a renal transplant in our center between January 1, 2000 and July 1, 2004. Other variables expected to influence the risks were included. RESULTS. In the Cox proportional hazards analysis the risk for graft failure censored for death was significantly influenced by pretransplant PTH concentration (P = 0.008) and donor type (P < 0.001). The influence of PTH on the risk for patient death was not significant. The risk for acute rejection was studied but PTH level did not have a significant influence on this risk (P = 0.055). The risk for delayed graft function was not influenced by PTH level. CONCLUSION: Serum PTH levels have an independent influence on the risk for graft failure censored for death. Efforts to improve calcium-phosphate-PTH homeostasis in patients on the waiting list for renal transplantation should be encouraged also to improve graft survival.

Stretch-induced modulation of matrix metalloproteinases in mineralizing osteoblasts via extracellular signal-regulated kinase-1/2.

Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) produced by osteoblasts play an essential role in bone remodeling. Hence, these proteins could provide an interesting means by which mechanical loading leads to adaptation of bone. Here, we examined the effect of stretch on MMP-1, -2, -3, -8, -9, -13, and -14, as well as TIMP-1 and -2 gene expression in differentiating, mineralizing, and nonmineralizing human SV-40 immortalized preosteoblast cells. In the mineralizing osteoblast culture, but not in the nonmineralizing cultures, cyclic stretch for only 15 min resulted in an increase of MMP-1 (fourfold) and -3 (depending on differentiation stage up to 25-fold) transcript abundance. No clear effect was observed for other MMPs, TIMP-1 or -2. The increase of MMP-1 and -3 was confirmed on the protein level. Stretching experiments performed in the presence of a specific inhibitor of extracellular signal-regulated kinase (ERK) showed a strong suppression of the stretch-induced increase in MMP-1 and -3. In conclusion, we show that MMP-1 and MMP-3 are mechanosensitive genes in mineralizing the human osteoblast, and that the mechano-induction of these genes is mediated via the ERK pathway. Our findings implicate that these MMPs are important factors in the mechanoregulation of bone turnover. With the ability to generate MMPs at highly stretched sites, osteoblasts can potantially direct osteoclasts to specific bone surface areas prepared for resorption.

Course and prognostic factors of disability in community-dwelling older people with mild disability: the Rotterdam Study.

AIM: To study the prognosis of disability of community-dwelling older people with mild disability at baseline. METHODS: We used data from the Rotterdam Study: a community-based prospective cohort study of community-dwelling older people. We evaluated sociodemographic factors, lifestyle variables, health conditions and disability status at baseline and follow-up after 6 years. Disability was defined as a score on the Health Assessment Questionnaire. RESULTS: At baseline the population consisted of 1166 older people with mild disability with a mean age of 69.7 (55-93) years. At follow-up 18% of the study population recovered from mild disability, 20% stayed mildly disabled, 31% became severely disabled, while 32% were deceased. At follow-up relatively more men died while more women had a worsened disability. Age and income were predictors of disability decrease. Alcohol use seemed to be significantly protective against death. CONCLUSION: Just a few prognostic factors appeared to be related to disability 6 years later.

Risk of falls after withdrawal of fall-risk-increasing drugs: a prospective cohort study.

AIMS: Falling in older persons is a frequent and serious clinical problem. Several drugs have been associated with increased fall risk. The objective of this study was to identify differences in the incidence of falls after withdrawal (discontinuation or dose reduction) of fall-risk-increasing drugs as a single intervention in older fallers. METHODS: In a prospective cohort study of geriatric outpatients, we included 139 patients presenting with one or more falls during the previous year. Fall-risk-increasing drugs were withdrawn, if possible. The incidence of falls was assessed within 2 months of follow-up after a set 1 month period of drug withdrawal. Multivariate adjustment for potential confounders was performed with a Cox proportional hazards model. RESULTS: In 67 patients, we were able to discontinue a fall-risk-increasing drug, and in eight patients to reduce its dose. The total number of fall incidents during follow-up was significantly lower in these 75 patients, than in those who continued treatment (mean number of falls: 0.3 vs. 3.6; P value 0.025). The hazard ratio of a fall during follow-up was 0.48 (95% confidence interval (CI) 0.23, 0.99) for overall drug withdrawal, 0.35 (95% CI 0.15, 0.82) for cardiovascular drug withdrawal and 0.56 (95% CI 0.23, 1.38) for psychotropic drug withdrawal, after adjustment for age, gender, use of fall-risk-increasing drugs, baseline falls frequency, comorbidity, Mini-Mental State Examination score, and reason for referral. CONCLUSIONS: Withdrawal of fall-risk-increasing drugs appears to be effective as a single intervention for falls prevention in a geriatric outpatient setting. The effect was greatest for withdrawal of cardiovascular drugs.

Incidence and risk factors of disability in the elderly: the Rotterdam Study.

BACKGROUND: This study analyzed the incidence of disability and its risk factors in multiple dimensions in community-dwelling women and men of older age, between 1990 and 1999, in Rotterdam, The Netherlands. METHODS: For this community-based prospective longitudinal study, data were obtained from the Rotterdam Study that comprised a cohort of 7983 elderly who are 55 and over. The study sample for incident disability consisted of 4258 subjects who were disability free at baseline and had complete outcome data at follow-up, 6 years later. Sociodemographic factors, lifestyle variables, health conditions and disability status were assessed at baseline and follow-up. Disability was defined as a Disability Index (DI) > or =0.50 according to the Health Assessment Questionnaire. RESULTS: Multivariate analyses, performed separately due to gender differences, revealed that age, self-rated health, overweight, depression, joint complaints, medication use were predictors of disability for both men and women. Stroke, falling and presence of comorbidities predicted disability in men only while having a partner, poor cognitive functioning, osteoarthritis and morning stiffness only predicted disability in women. CONCLUSION: Identified risk factors in this study are to some extent modifiable, enabling interventive strategies, reckoning with gender differences in risk profile, in order to prevent disability.

Characterization of a promoter polymorphism in the glucocorticoid receptor gene and its relationship to three other polymorphisms.

OBJECTIVE: Sensitivity to glucocorticoids within the normal population is highly variable and partly determined by polymorphisms in the glucocorticoid receptor (GR) gene (NR3C1). We investigated the exact sequence alteration of a TthIIII polymorphism in the GR gene, whether it is associated with glucocorticoid sensitivity, and its relationship to 3 polymorphisms of the GR gene (N363S, BclI, ER22/23EK). DESIGN: Two dexamethasone (DEX) suppression tests were performed with 1 and 0.25 mg DEX, respectively. PATIENTS: We genotyped a random subgroup of 209 participants of the Rotterdam Study, a population-based study in the elderly. MEASUREMENTS: Anthropometric parameters, cortisol, insulin and glucose levels, and lipid concentrations were measured. RESULTS: We identified the TthIIII polymorphism as a C to T mutation, 3807 bp upstream from the mRNA start site. We found 39.7% CC-carriers, 44.5% CT-carriers, and 15.8 % TT-carriers. No differences were found between TthIIII genotypes in sensitivity to DEX, baseline cortisol, insulin, glucose or cholesterol levels, or in anthropometric variables. However, all ER22/23EK-carriers also carried the TthIIII T-allele, and carriers of both these polymorphisms had a significantly smaller cortisol suppression after 1 mg DEX, lower fasting insulin levels, and lower total and low-density lipoprotein (LDL) cholesterol levels than TthIIII T carriers without the ER22/23EK variant and noncarriers. No interaction was found between the TthIIII variant and N363S or BclI polymorphisms. CONCLUSIONS: The TthIIII polymorphism is not functional by itself. However, the ER22/23EK polymorphism is without exception linked to the TthIIII T polymorphism and this haplotype is associated with a relative resistance to glucocorticoids, and a healthy metabolic profile.

A cross-sectional study on biochemical parameters of bone turnover and vitamin d metabolites in healthy dutch children and young adults.

AIM: To provide reference data of biochemical markers of bone turnover and vitamin D metabolites for children and young adults. METHODS: Blood samples were taken from 176 healthy Dutch children and young adults (age range 7.6-25.3 years) to assess serum calcium, alkaline phosphatase, inorganic phosphate, osteocalcin, collagen type I cross-linked N-telopeptide, N-terminal propeptide of type I procollagen, 25-hydroxyvitamin D3, and 1,25-dihydroxyvitamin D3 levels. Cross-linked telopeptide of type I collagen and carboxy-terminal propeptide of type I procollagen were assessed in 286 subjects (age range 1.4-25.3 years). RESULTS: Calcium and vitamin D levels were independent of age. The peak concentrations for collagen type I cross-linked N-telopeptide, cross-linked telopeptide of type I collagen, carboxy-terminal propeptide of type I procollagen, N-terminal propeptide of type I procollagen, alkaline phosphatase, and osteocalcin were found during puberty, in girls approximately 2.5 years earlier than in boys. Strong correlations were found between the markers of bone turnover, while no correlation was found between the markers of bone turnover and bone mineral density measured by dual-energy X-ray absorptiometry. CONCLUSIONS: Single measurements of bone markers cannot predict bone density. Reference data according to gender, age, and Tanner stage are given which allow calculating standard deviation scores adjusted for age and gender.