Fat metabolism is associated with telomere length in six population-based studies.

Telomeres are repetitive DNA sequences located at the end of chromosomes, which are associated to biological aging, cardiovascular disease, cancer and mortality. Lipid and fatty acid metabolism have been associated with telomere shortening. We have conducted an in-depth study investigating the association of metabolic biomarkers with telomere length (LTL). We performed an association analysis of 226 metabolic biomarkers with LTL using data from 11 775 individuals from six independent population-based cohorts (BBMRI-NL consortium). Metabolic biomarkers include lipoprotein lipids and subclasses, fatty acids, amino acids, glycolysis measures and ketone bodies. LTL was measured by quantitative polymerase chain reaction or FlowFISH. Linear regression analysis was performed adjusting for age, sex, lipid-lowering medication and cohort-specific covariates (model 1) and additionally for body mass index (BMI) and smoking (model 2), followed by inverse variance-weighted meta-analyses (significance threshold Pmeta = 6.5 × 10-4). We identified four metabolic biomarkers positively associated with LTL, including two cholesterol to lipid ratios in small VLDL (S-VLDL-C % and S-VLDL-CE %) and two omega-6 fatty acid ratios (FAw6/FA and LA/FA). After additionally adjusting for BMI and smoking, these metabolic biomarkers remained associated with LTL with similar effect estimates. In addition, cholesterol esters in very small VLDL (XS-VLDL-CE) became significantly associated with LTL (P = 3.6 × 10-4). We replicated the association of FAw6/FA with LTL in an independent dataset of 7845 individuals (P = 1.9 × 10-4). To conclude, we identified multiple metabolic biomarkers involved in lipid and fatty acid metabolism that may be involved in LTL biology. Longitudinal studies are needed to exclude reversed causation.

Short-Term, Combined Fasting and Exercise Improves Body Composition in Healthy Males.

Fasting enhances the beneficial metabolic outcomes of exercise; however, it is unknown whether body composition is favorably modified on the short term. A baseline-follow-up study was carried out to assess the effect of an established protocol involving short-term combined exercise with fasting on body composition. One hundred seven recreationally exercising males underwent a 10-day intervention across 15 fitness centers in the Netherlands involving a 3-day gradual decrease of food intake, a 3-day period with extremely low caloric intake, and a gradual 4-day increase to initial caloric intake, with daily 30-min submaximal cycling. Using dual-energy X-ray absorptiometry analysis, all subjects substantially lost total body mass (-3.9 ± 1.9 kg; p < .001) and fat mass (-3.3 ± 1.3 kg; p < .001). Average lean mass was lost (-0.6 ± 1.5 kg; p < .001), but lean mass as a percentage of total body mass was not reduced. The authors observed a loss of -3.9 ± 1.9% android fat over total fat mass (p < .001), a loss of -2.2 ± 1.9% gynoid over total fat mass (p < .001), and reduced android/gynoid ratios (-0.05 ± 0.1; p < .001). Analyzing 15 preselected single-nucleotide polymorphisms in 13 metabolism-related genes revealed trending associations for thyroid state-related single-nucleotide polymorphisms rs225014 (deiodinase 2) and rs35767 (insulin-like growth factor1), and rs1053049 (PPARD). In conclusion, a short period of combined fasting and exercise leads to a substantial loss of body and fat mass without a loss of lean mass as a percentage of total mass.

Exome Sequencing Analysis Identifies Rare Variants in ATM and RPL8 That Are Associated With Shorter Telomere Length.

Telomeres are important for maintaining genomic stability. Telomere length has been associated with aging, disease, and mortality and is highly heritable (∼82%). In this study, we aimed to identify rare genetic variants associated with telomere length using whole-exome sequence data. We studied 1,303 participants of the Erasmus Rucphen Family (ERF) study, 1,259 of the Rotterdam Study (RS), and 674 of the British Heart Foundation Family Heart Study (BHF-FHS). We conducted two analyses, first we analyzed the family-based ERF study and used the RS and BHF-FHS for replication. Second, we combined the summary data of the three studies in a meta-analysis. Telomere length was measured by quantitative polymerase chain reaction in blood. We identified nine rare variants significantly associated with telomere length (p-value < 1.42 × 10-7, minor allele frequency of 0.2-0.5%) in the ERF study. Eight of these variants (in C11orf65, ACAT1, NPAT, ATM, KDELC2, and EXPH5) were located on chromosome 11q22.3 that contains ATM, a gene involved in telomere maintenance. Although we were unable to replicate the variants in the RS and BHF-FHS (p-value ≥ 0.21), segregation analysis showed that all variants segregate with shorter telomere length in a family. In the meta-analysis of all studies, a nominally significant association with LTL was observed with a rare variant in RPL8 (p-value = 1.48 × 10-6), which has previously been associated with age. Additionally, a novel rare variant in the known RTEL1 locus showed suggestive evidence for association (p-value = 1.18 × 10-4) with LTL. To conclude, we identified novel rare variants associated with telomere length. Larger samples size are needed to confirm these findings and to identify additional variants.

Genome-wide Association Analysis in Humans Links Nucleotide Metabolism to Leukocyte Telomere Length.

Leukocyte telomere length (LTL) is a heritable biomarker of genomic aging. In this study, we perform a genome-wide meta-analysis of LTL by pooling densely genotyped and imputed association results across large-scale European-descent studies including up to 78,592 individuals. We identify 49 genomic regions at a false dicovery rate (FDR) < 0.05 threshold and prioritize genes at 31, with five highlighting nucleotide metabolism as an important regulator of LTL. We report six genome-wide significant loci in or near SENP7, MOB1B, CARMIL1, PRRC2A, TERF2, and RFWD3, and our results support recently identified PARP1, POT1, ATM, and MPHOSPH6 loci. Phenome-wide analyses in >350,000 UK Biobank participants suggest that genetically shorter telomere length increases the risk of hypothyroidism and decreases the risk of thyroid cancer, lymphoma, and a range of proliferative conditions. Our results replicate previously reported associations with increased risk of coronary artery disease and lower risk for multiple cancer types. Our findings substantially expand current knowledge on genes that regulate LTL and their impact on human health and disease.

Telomere Length and the Risk of Alzheimer's Disease: The Rotterdam Study.

There is a wide interest in biomarkers that capture the burden of detrimental factors as these accumulate with the passage of time, i.e., increasing age. Telomere length has received considerable attention as such a marker, because it is easily quantified and it may aid in disentangling the etiology of dementia or serve as predictive marker. We determined the association of telomere length with risk of Alzheimer's disease and all-cause dementia in a population-based setting. Within the Rotterdam Study, we performed quantitative PCR to measure mean leukocyte telomere length in blood. We determined the association of telomere length with risk of Alzheimer's disease until 2016, using Cox regression models. Of 1,961 participants (mean age 71.4±9.3 years, 57.1% women) with a median follow-up of 8.3 years, 237 individuals were diagnosed with Alzheimer's disease. We found a U-shaped association between telomere length and risk of Alzheimer's disease: compared to the middle tertile the adjusted hazard ratio was 1.59 (95% confidence interval (CI), 1.13-2.23) for the lowest tertile and 1.47 (1.03-2.10) for the highest tertile. Results were similarly U-shaped but slightly attenuated for all-cause dementia. In conclusion, shorter and longer telomere length are both associated with an increased risk of Alzheimer's disease in the general population.

Population-specific genetic variation in large sequencing data sets: why more data is still better.

We have generated a next-generation whole-exome sequencing data set of 2628 participants of the population-based Rotterdam Study cohort, comprising 669 737 single-nucleotide variants and 24 019 short insertions and deletions. Because of broad and deep longitudinal phenotyping of the Rotterdam Study, this data set permits extensive interpretation of genetic variants on a range of clinically relevant outcomes, and is accessible as a control data set. We show that next-generation sequencing data sets yield a large degree of population-specific variants, which are not captured by other available large sequencing efforts, being ExAC, ESP, 1000G, UK10K, GoNL and DECODE.

Vitamin D Receptor Polymorphisms Are Associated with Reduced Esophageal Vitamin D Receptor Expression and Reduced Esophageal Adenocarcinoma Risk.

Epidemiological studies indicate that vitamin D exerts a protective effect on the development of various solid cancers. However, concerns have been raised regarding the potential deleterious role of high vitamin D levels in the development of esophageal adenocarcinoma (EAC). This study investigated genetic variation in the vitamin D receptor (VDR) in relation to its expression and risk of Barrett esophagus (BE) and EAC. VDR gene regulation was investigated by immunohistochemistry, reverse transcriptase-polymerase chain reaction (RT-PCR) and gel shift assays. Fifteen haplotype tagging single-nucleotide polymorphisms (SNPs) of the VDR gene were analyzed in 858 patients with reflux esophagitis (RE), BE or EAC and 202 healthy controls. VDR mRNA expression was higher in BE compared with squamous epithelium. VDR protein was located in the nucleus in BE. An rs1989969T/rs2238135G haplotype was identified in the 5' regulatory region of the VDR gene. It was associated with an approximately two-fold reduced risk of RE, BE and EAC. Analysis of a replication cohort was done for BE that confirmed this. The rs1989969T allele causes a GATA-1 transcription factor binding site to appear. The signaling of GATA-1, which is regarded as a negative transcriptional regulator, could explain the findings for rs1989969. The rs2238135G allele was associated with a significantly reduced VDR expression in BE; for the rs1989969T allele, a trend in reduced VDR expression was observed. We identified a VDR haplotype associated with reduced esophageal VDR expression and a reduced incidence of RE, BE and EAC. This VDR haplotype could be useful in identifying individuals who benefit most from vitamin D chemoprevention.

Recognition of scared faces and the serotonin transporter gene in young children: the Generation R Study.

BACKGROUND: Previous research highlights the significance of a functional polymorphism located in the promoter region (5-HTTLPR) of the serotonin transporter gene in emotional behaviour. This study examined the effect of the 5-HTTLPR polymorphism on emotion processing in a large number of healthy preschoolers. METHODS: The 5-HTTLPR genotype was classified in 605 children as homozygous for the short allele (SS), homozygous for the long allele (LL), or heterozygous (LS). Emotion-processing was assessed using age-appropriate computer tasks where children matched happy, sad, angry, and fearful facial expressions preceded by a shape-matching task to assess basic matching ability. RESULTS: We found that young children could differentiate between emotion categories (F = 12.1, p < .001). The effect of 5-HTTLPR genotype depended on the emotion category presented (F = 2.3, p = .031). This effect was explained by the finding that SS children were less accurate at recognising fearful faces than LL or LS children (F = 5.3, p = .005). We did not find any significant differences as a result of 5-HTTLPR genotype for happy, sad or angry expressions (p > .05). CONCLUSIONS: Results indicate that 5-HTTLPR allele status selectively impacts the processing of fearful but not other facial expressions. This pattern is already apparent in very young typically developing children. Results may signal an early vulnerability for affective problems before disorders emerge.

Serotonin transporter polymorphism moderates effects of prenatal maternal anxiety on infant negative emotionality.

BACKGROUND: Consistent with the fetal programming hypothesis, effects of maternal prenatal anxiety have been found to predict various measures of infant temperament in the early postnatal period. In recent years, a polymorphism in the serotonin transporter gene (5-HTTLPR) emerged as a moderator of diverse environmental influences on different outcomes, with individuals carrying the short allele being generally more vulnerable to adversity. METHODS: We tested whether the association between self-reported maternal anxiety at 20 weeks gestation (Brief Symptom Inventory) and mother-rated infant negative emotionality at 6 months after birth (Infant Behavior Questionnaire-Revised) would be moderated by the 5-HTTLPR in a large Dutch cohort sample (n = 1513). We hypothesized that infants carrying the 5-HTTLPR short allele would be more susceptible and therefore more affected by both low and high prenatal maternal anxiety vis-à-vis negative emotionality than other genotypes. RESULTS: Findings of a significant gene × environment interaction (B = .65, p = .01) were supportive of a vulnerability model, with infants carrying the short allele being more negatively emotional when mothers reported anxiety during pregnancy, whereas there was no difference between genotypes on negative emotionality when maternal anxiety was low. CONCLUSIONS: The association between maternal anxiety during pregnancy and negative emotionality in early infancy was significant in infants carrying one or more copies of the short allele but not in those homozygous for the long allele. The 5-HTTLPR short allele might increase vulnerability to adverse environmental influences as early as the fetal period.

The interleukin-6-174 G/C promoter polymorphism and arterial stiffness; the Rotterdam Study.

Arterial stiffness normally increases with age and has been established as a precursor of cardiovascular disease. Interleukin-6 is a pleiotropic inflammatory cytokine with an important role in the inflammatory cascade, such as up-regulation of C-reactive protein (CRP). The interleukin-6-174-G/C promoter polymorphism appears to influence levels of inflammatory markers, which have been shown to be associated with arterial stiffness. We studied the association of this polymorphism with levels of interleukin-6 and CRP and with arterial stiffness. The study (n=3849) was embedded in the Rotterdam Study, a prospective, population-based study. Analyses on the association between the -174-G/C polymorphism and pulse wave velocity, distensibility coefficient, and pulse pressure were performed using analyses of variance. Analyses on the levels of inflammatory markers and arterial stiffness were performed using linear regression analyses. Analyses were adjusted for age, sex, mean arterial pressure, heart rate, known cardiovascular risk factors, and atherosclerosis. We found pulse wave velocity to be 0.35 m/s higher for CC-homozygotes vs. wildtype GG-homozygotes (p = 0.018) with evidence for an allele-dose effect (p trend = 0.013), and a similar pattern for pulse pressure (p trend = 0.041). No apparent consistent association with the distensibility coefficient was found. CRP levels were associated with pulse wave velocity (p = 0.007). In conclusion, the interleukin-6-174 G/C polymorphism is associated with increased arterial stiffness and pulse pressure.

Common ATP-binding cassette B1 variants are associated with increased digoxin serum concentration.

BACKGROUND AND OBJECTIVE: Digoxin is a known substrate of ATP-binding cassette B1 (ABCB1/MDR1). The results of studies on the association between ABCB1 polymorphisms and digoxin kinetics, however, remain contradictory. Almost all studies were small and involved only single dose kinetics. The goal of this study was to establish ABCB1 genotype effect on digoxin blood concentrations in a large cohort of chronic digoxin users in a general Dutch European population. METHODS: Digoxin users were identified in the Rotterdam Study, a prospective population-based cohort study of individuals aged 55 years and above. Digoxin blood levels were gathered from regional hospitals and laboratories. ABCB1 single nucleotide polymorphisms (SNPs) 1236C-->T, 2677G-->T/A, and 3435C-->T were assessed on peripheral blood DNA using Taqman assays. We studied the association between the ABCB1 genotypes and haplotypes, and digoxin blood levels using linear regression models adjusting for potential confounders. RESULTS: Digoxin serum levels and DNA were available for 195 participants (56.4% women, mean age 79.4 years). All three ABCB1 variants were significantly associated with serum digoxin concentration (0.18-0.21 microg/l per additional T allele). The association was even stronger for the 1236-2677-3435 TTT haplotype allele [0.26 mug/l (95% CI 0.14-0.38)], but absent for other haplotypes (CGC allele considered referent), suggesting an interaction of SNPs in a causal haplotype instead of individual SNP effects. CONCLUSION: We found that the common ABCB1 1236C-->T, 2677G-->T, and 3435C-->T variants and the associated TTT haplotype were associated with higher digoxin serum concentrations in a cohort of elderly European digoxin users in the general population.

Large-scale analysis of association between polymorphisms in the transforming growth factor beta 1 gene (TGFB1) and osteoporosis: the GENOMOS study.

INTRODUCTION: The TGFB1 gene which encodes transforming growth factor beta 1, is a strong candidate for susceptibility to osteoporosis and several studies have reported associations between bone mineral density (BMD), osteoporotic fractures and polymorphisms of TGFB1, although these studies have yielded conflicting results. METHODS: We investigated associations between TGFB1 polymorphisms and BMD and fracture in the GENOMOS study: a prospective multicenter study involving 10 European research studies including a total of 28,924 participants. Genotyping was conducted for known TGFB1 polymorphisms at the following sites: G-1639-A (G-800-A, rs1800468), C-1348-T (C-509-T, rs1800469), T29-C (Leu10Pro, rs1982073), G74-C (Arg25Pro, rs1800471) and C788-T (Thr263Ile, rs1800472). These polymorphisms were genotyped prospectively and methodology was standardized across research centers. Genotypes and haplotypes were related to BMD at the lumbar sine and femoral neck and fractures. RESULTS: There were no significant differences in either women or men at either skeletal site for any of the examined polymorphisms with the possible exception of a weak association with reduced BMD (-12 mg/cm2) in men with the T-1348 allele (p<0.05). None of the haplotypes was associated with BMD and none of the polymorphisms or haplotypes significantly affected overall risk of fractures, however, the odds ratio for incident vertebral fracture in carriers of the rare T788 allele was 1.64 (95% CI: 1.09-2.64), p<0.05. CONCLUSIONS: This study indicates that polymorphic variation in the TGFB1 gene does not play a major role in regulating BMD or susceptibility to fractures. The weak associations we observed between the C-1348-T and lumbar spine BMD in men and between C788-T and risk of incident vertebral fractures are of interest but could be chance findings and will need replication in future studies.

The RIZ Pro704 insertion-deletion polymorphism, bone mineral density and fracture risk: the Rotterdam study.

Estrogens play a major role in the maintenance of bone and bone strength, and they exert their effects via estrogen receptors. Recently, an estrogen receptor alpha (ESR1) specific co-activator, retinoblastoma-interacting zinc-finger protein (RIZ1, 1p36), was shown to strongly enhance ESR1 function in vitro. The same study showed that a Proline insertion-deletion polymorphism at amino acid position 704 (Pro704 ins/del) in the RIZ1 gene was associated with heel BMD in young Swedish women. We tested the relation between the RIZ1 Pro704 ins/del polymorphism and BMD and fracture risk in Caucasian elderly men and women of the Rotterdam study. We also examined whether estradiol levels (measured in a subset) or genetic variation in ESR1 influenced this relation. In 2424 men and 3517 women from the Rotterdam study, RIZ1 genotypes were determined and associations with BMD (lumbar spine and femoral neck) and fracture risk were analysed. We recorded 374 vertebral fractures at baseline and during 6.4+/-0.4 (SD) years of follow-up, and 1219 incident non-vertebral fractures during 7.4+/-3.3 (SD) years of follow-up. The allele frequency of the Pro704 insertion was 41%, the genotype distribution was in Hardy-Weinberg Equilibrium (P=0.94). We found no association of this polymorphism with BMD or fracture risk. Stratification for gender, estradiol levels or interaction with ESR1 risk haplotype did not change these results. In conclusion, in this large study we observed no association of the RIZ1 Pro704 insertion-deletion polymorphism with BMD or fracture risk. This suggests this polymorphism to play a minor role, if any, as a genetic determinant of osteoporosis in elderly subjects.

The catechol-O-methyltransferase Met158 low-activity allele and association with nonvertebral fracture risk in elderly men.

CONTEXT: Because sex steroids play an important role in bone development, variants in genes encoding proteins involved in estrogen synthesis and metabolism could contribute to interindividual variation in bone parameters and fracture risk. An example is catechol-O-methyltransferase (COMT), an estrogen-degrading enzyme involved in inactivation of catechol-estrogens. Its gene contains a functional valine to methionine substitution at codon 158. OBJECTIVE: The aim of our study was to determine whether this polymorphism is associated with bone parameters and fracture risk in elderly subjects. METHODS: COMT genotypes were determined using TaqMan allelic discrimination in 2515 men and 3554 women from the Rotterdam Study, a population-based cohort study of individuals aged 55 and older. Associations with bone mineral density (BMD) and bone loss were analyzed using ANOVA or analysis of covariance, whereas fracture risk was analyzed using Cox's proportional hazard regression analysis. COMT mRNA expression in three osteoblastic cell lines (SaOS, MG63, and SVHFO) was analyzed by RT-PCR. RESULTS: Male carriers of the Met(158) allele had an increased risk for osteoporotic fractures (hazard ratio = 1.6; 95% confidence interval, 1.0-2.4) and for fragility fractures (hazard ratio = 2.7; 95% confidence interval, 1.3-5.9), with evidence for a dominant effect. Adjustments for age, height, weight, and BMD did not change the risk estimates. In women, this association was weaker and not significant. BMD was not significantly associated with the variant in either men or women. COMT mRNA was expressed in all three osteoblastic cell lines tested. CONCLUSION: The COMT Val158Met polymorphism is associated with fracture risk in elderly men, through a mechanism independent of BMD.

TGF-beta 1 polymorphisms and risk of myocardial infarction and stroke: the Rotterdam Study.

BACKGROUND AND PURPOSE: Inflammation plays a pivotal role in the pathogenesis of atherosclerosis and of cardiovascular and cerebrovascular complications. Transforming growth factor-beta1 (TGF-beta1) is a pleiotropic cytokine with a central role in inflammation. Little is known of the relation of variations within the gene and risk of cardiovascular and cerebrovascular disease. We therefore investigated 5 polymorphisms in the TGF-beta1 gene (-800 G/A, -509 C/T, codon 10 Leu/Pro, codon 25 Arg/Pro, and codon 263 Thr/Ile) in relation to the risk of myocardial infarction and stroke in a population-based study. METHODS: Participants (N=6456) of the Rotterdam Study were included in the current study. Analyses of the relations of genotypes with the risk of myocardial infarction and stroke were performed according to Cox proportional-hazards methods. All analyses were adjusted for age, sex, conventional cardiovascular risk factors, and medical history. RESULTS: We found no association with the risk of myocardial infarction. A significantly increased risk of stroke was found, associated with the T allele of the -509 C/T polymorphism (relative risk, 1.26; (95% CI, 1.06 to 1.49) and the Pro variant of the codon 10 polymorphism (relative risk, 1.24; 95% CI, 1.04 to 1.48). CONCLUSIONS: No association between the TGF-beta1 polymorphisms and myocardial infarction was observed; however, the -509 C/T and codon 10 Leu/Pro polymorphisms were associated with the risk of stroke.

BMP-2 gene polymorphisms and osteoporosis: the Rotterdam Study.

UNLABELLED: After reported associations of variations in the BMP-2 gene with osteoporosis in small populations, we studied the association of the BMP-2 gene polymorphisms Ser37Ala and Arg190Ser with osteoporosis in 6353 men and women from the Rotterdam Study. We did not observe an association of these variants with BMD, bone loss, hip structural analysis parameters, and fracture risk. INTRODUCTION: Bone morphogenetic protein 2 (BMP-2) plays a role in osteoblast differentiation. BMP-2 gene variation has previously been associated with osteoporosis in various small populations, but current evidence remains inconclusive about the exact association with osteoporosis. Therefore, we studied the association of two polymorphisms located in the BMP-2 gene (Ser37Ala and Arg190Ser) and haplotypes defined by these polymorphisms with BMD, rates of bone loss, parameters of hip structural analysis (HSA), and fractures in the Rotterdam Study, a large prospective cohort study of diseases in the elderly. MATERIALS AND METHODS: Databases were searched for polymorphisms and haplotype blocks in the BMP-2 gene region. Allele frequencies for Ser37Ala and Arg190Ser were determined in 60 blacks and 110 Chinese from Coriell panels. Genotype data on Ser37Ala and Arg190Ser were available for 6353 individuals from the Rotterdam Study population. Haplotype alleles defined by Ser37Ala and Arg190Ser were inferred using PHASE software. Genotype and haplotype analyses for BMD (measured at the lumbar spine and femoral neck), bone loss per year (measured at the femoral neck), and HSA were performed using AN(C)OVA. Fractures were analyzed using a Cox proportional-hazards model and logistic regression. All outcomes were adjusted for age, height, and weight. RESULTS: Allele frequencies were 2.5% for Ala37 and 40.2% for Ser190, whereas haplotype allele frequencies were 57.28% (Ser37Arg190), 40.19% (Ser37Ser190), 2.50% (Ala37Arg190), and 0.02% (Ala37Ser190). For BMD, bone loss, HSA outcomes, and (incident) fractures, no differences could be seen between genotype and haplotype groups. CONCLUSIONS: In this large population-based cohort of Dutch whites, we conclude that the BMP-2 Ser37Ala and Arg190Ser polymorphisms or haplotypes thereof are not associated with parameters of osteoporosis.

Polymorphisms in the interleukin 6 and transforming growth factor beta1 gene and risk of dementia. The Rotterdam Study.

Inflammatory mechanisms are involved in the pathogenesis of dementia. Inflammatory cytokines, including interleukin-6 (IL-6) and transforming growth factor beta1 (TGFbeta1), have been found in association with Alzheimer pathology and there is evidence for direct involvement of these cytokines in formation of amyloid plaques. Polymorphisms in genes encoding for IL-6 and TGFbeta1 are associated with plasma levels of IL-6 and TGFbeta1. Studies examining the association between polymorphisms in these genes and dementia yielded conflicting results. The purpose of this study was to examine the association between genetic variance in IL-6 and TGFbeta1 and risk of dementia. We examined this association in the Rotterdam Study, a prospective population-based cohort study in the elderly. Polymorphisms in the IL-6 (-174G>C) and TGFbeta1 gene (-800G>A, -509C>T, +10T>C, +25G>C and 263C>T) were genotyped and haplotypes of the TGFbeta1 gene were constructed. In a random subset IL-6 plasma levels were measured. During follow-up (mean 9.2 years), 743 dementia cases were identified. We estimated the association between individual polymorphisms and haplotypes with dementia with Cox' proportional hazard models. No association was found between the -174G>C polymorphism in the IL-6 gene and risk of dementia. No association was found between polymorphisms and constructed haplotypes in the TGFbeta1 gene and risk of dementia or Alzheimer's disease. No association was found between IL-6 genotype and IL-6 plasma levels in the random subset. Associations did not differ across APOE genotypes. Our findings do not suggest involvement of genetic variance in IL-6 and TGFbeta1 in the development of dementia.

Polymorphisms in the sclerosteosis/van Buchem disease gene (SOST) region are associated with bone-mineral density in elderly whites.

Osteoporosis has a strong genetic component, but the genes involved are poorly defined. We studied whether the sclerosteosis/van Buchem disease gene (SOST) is an osteoporosis-risk gene by examining its association with bone-mineral density (BMD). Mutations in SOST result in sclerosteosis, and alterations in the SOST gene expression may be causal in the closely related van Buchem disease. We used a set of eight polymorphisms from the SOST gene region to genotype 1,939 elderly men and women from a large population-based prospective-cohort study of Dutch whites. A 3-bp insertion (f=0.38) in the presumed SOST promoter region (SRP3) was associated with decreased BMD in women at the femoral neck (FN) (P=.05) and lumbar spine (LS) (P=.01), with evidence of an allele-dose effect in the oldest age group (P=.006). Similarly, a G variant (f=0.40) in the van Buchem deletion region (SRP9) was associated with increased BMD in men at the FN (P=.007) and LS (P=.02). In both cases, differences between extreme genotypes reached 0.2 SD. We observed no genotype effects on fracture risk, for the 234 osteoporotic fractures validated during 8.2 years of follow-up and for the 146 vertebral prevalent fractures analyzed. We did not find association between any of several frequent haplotypes across the SOST gene region and BMD. We did find evidence of additive effects of SRP3 with the COLIA1 Sp1 polymorphism but not with haplotypes of 3' polymorphisms in the vitamin-D receptor gene. The SOST-COLIA1 additive effect increased with age and reached 0.5 SD difference in BMD at LS in the oldest age group (P=.02). The molecular mechanism whereby these moderate SOST genotype effects are mediated remains to be elucidated, but it is likely to involve differences in regulation of SOST gene expression.

Estrogen receptor alpha gene haplotype is associated with radiographic osteoarthritis of the knee in elderly men and women.

OBJECTIVE: Genetic influences have been shown to play an important role in the etiology of osteoarthritis (OA), but the genes involved are ill-defined. We studied the association between polymorphisms in the estrogen receptor alpha (ERalpha) gene and the prevalence of radiographic OA of the knee. METHODS: The study group comprised 1,483 men and women from the Rotterdam Study. Direct molecular haplotyping was used to determine the relationship between 2 polymorphisms in the ERalpha gene (the Pvu II and Xba I restriction fragment-length polymorphisms). Radiographs of the knee were evaluated according to the Kellgren/Lawrence (K/L) score, along with separate scores for osteophytosis and joint space narrowing. RESULTS: Three different haplotype alleles were identified: px (54%), PX (34%), and Px (12%). Allele PX was associated with an increased prevalence of radiographic knee OA (K/L score >/=2). The prevalence of radiographic OA was 22% among subjects without allele PX, 24% among those carrying 1 copy, and 35% among subjects carrying 2 copies. The corresponding odds ratios, after adjustment for confounding factors, were 1.3 (95% confidence interval [95% CI] 0.9-1.7) for heterozygotes and 2.2 (95% CI 1.5-3.4) for homozygotes. Separate analyses for men and women showed similar risk estimates. The association appeared to be driven by osteophytosis and is somewhat consistent with the association observed in previous studies of these polymorphisms in relation to OA. CONCLUSION: This study shows that polymorphisms in the ERalpha gene are associated with radiographic OA of the knee, and in particular with osteophytosis, in both elderly men and elderly women.

Association of 5' estrogen receptor alpha gene polymorphisms with bone mineral density, vertebral bone area and fracture risk.

This study investigates the influence of genetic variation of the estrogen receptor alpha (ESR1) gene locus on several bone parameters in 2042 individuals of The Rotterdam Study, a prospective population-based cohort study of elderly subjects. We analysed three polymorphic sites in the 5' region of the ESR1 gene; a (TA)(n)-repeat in the promoter region, and molecular haplotypes of the PvuII and XbaI RFLPs in intron 1, and inferred long-range haplotypes (LRH) thereof. We observed only three of the possible four PvuII-XbaI haplotypes in our population. A comparison with other Caucasian populations showed similar haplotype frequencies, while in Asian and African populations these were different. Linkage disequilibrium (LD) analysis between the PvuII-XbaI haplotype and the (TA)(n) repeat showed strong LD between the two sites. Reconstruction of long range haplotypes over the entire 5' region, revealed six frequent LRH. In men, we did not observe an association between the ESR1 polymorphisms studied and bone parameters. In women, we demonstrated an allele dose effect of haplotype "px" (P=0.003) and a low number of (TA)(n) repeats (P=0.008) with decreased lumbar spine bone mineral density (BMD) (4.8% lower BMD in women homozygous for haplotype "px", representing 28% of the population, compared with homozygous non-carriers) and decreased vertebral bone area (2.3% difference between extreme genotypes; P=0.016). Most importantly, we found an increased vertebral fracture risk with evidence for an allele dose effect with an odds ratio of 2.2 (95%CI 1.3-3.5) for haplotype "px", and 2.0 (1.5-3.2) for a low number of (TA)(n) repeats. The ESR1 genotype dependent fracture risk is largely independent of BMD and bone area. Combination of risk alleles at both loci by long-range haplotyping improved the associations slightly, but because of the strong LD between the two polymorphic sites, we were unable to determine if any particular polymorphic site is driving the associations found. We conclude that ESR1 polymorphism in the 5' (promoter) region is associated with vertebral fracture risk, lumbar spine BMD and vertebral bone area in postmenopausal women, but not in men. The molecular mechanism underlying this association needs further study.