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Biomedical subjects

Børge G Nordestgaard

Publications and source records attributed to Børge G Nordestgaard.

At least 19 recordsLinked to original sources

Improving prediction of ischemic cardiovascular disease in the general population using apolipoprotein B: the Copenhagen City Heart Study.

BACKGROUND: Apolipoprotein B (apoB) levels predict fatal myocardial infarction. Whether apoB also predicts nonfatal ischemic cardiovascular events is unclear. We tested the following hypotheses: apoB predicts ischemic cardiovascular events, and apoB is a better predictor of ischemic cardiovascular events than low-density lipoprotein cholesterol. METHODS AND RESULTS: We studied 9231 asymptomatic women and men from the Danish general population followed prospectively for 8 years and observed the following incident events: ischemic heart disease 591, myocardial infarction 278, ischemic cerebrovascular disease 313, ischemic stroke 229, and any ischemic cardiovascular event 807. Women with apoB in the upper versus the lower tertile had hazard ratios for ischemic heart disease of 1.8 (1.2 to 2.5), for myocardial infarction 2.6 (1.4 to 4.7), and for any ischemic cardiovascular event 1.8 (1.3 to 2.3), and men had hazard ratios for ischemic heart disease of 1.9 (1.5 to 2.6), for myocardial infarction 2.4 (1.5 to 3.6), and for any ischemic cardiovascular event 1.6 (1.3 to 2.1). Women had similar hazard ratios for ischemic cerebrovascular disease and ischemic stroke. ApoB had a higher predictive ability than low-density lipoprotein cholesterol in the prediction of ischemic heart disease, myocardial infarction, any ischemic cardiovascular event, and any nonfatal ischemic cardiovascular event in both genders (P=0.03 to <0.001). Finally, in smokers older than 60 years with systolic blood pressure >160 mm Hg, apoB contributed 11% in women and 15% in men to the increase in absolute 10-year risk from the lower to the upper apoB tertile. CONCLUSION: ApoB predicts ischemic cardiovascular events in both genders, and is better than low-density lipoprotein cholesterol in this respect. We suggest that prediction of future ischemic cardiovascular events could be improved by measuring apoB.

Adult↗

C-reactive protein as a predictor of prognosis in chronic obstructive pulmonary disease.

RATIONALE: Patients with chronic obstructive pulmonary disease (COPD) have an ongoing systemic inflammation, which can be assessed by measuring serum C-reactive protein (CRP). OBJECTIVE: To determine whether increased serum CRP in individuals with airway obstruction predicts future hospitalization and death from COPD. METHODS: We performed a cohort study with a median of 8-yr follow-up of 1,302 individuals with airway obstruction selected from the ongoing Copenhagen City Heart Study. MEASUREMENTS AND MAIN RESULTS: We measured serum CRP at baseline, and recorded COPD admissions and deaths as outcomes. During follow-up, 185 (14%) individuals were hospitalized due to COPD and 83 (6%) died of COPD. Incidences of COPD hospitalization and COPD death were increased in individuals with baseline CRP > 3 mg/L versus < or = 3 mg/L (log rank: p < 0.001). After adjusting for sex, age, FEV(1)% predicted, tobacco consumption, and ischemic heart disease, the hazard ratios for hospitalization and death due to COPD were increased at 1.4 (95% confidence interval, 1.0-2.0) and 2.2 (1.2-3.9) in individuals with baseline CRP > 3 mg/L versus < or = 3 mg/L. After close matching for FEV(1)% predicted and adjusting for potential confounders, baseline CRP was, on average, increased by 1.2 mg/L (analysis of variance: p = 0.002) and 4.1 mg/L (p = 0.001) in those who were subsequently hospitalized or died of COPD, respectively. The absolute 10-yr risks for COPD hospitalization and death in individuals with CRP above 3 mg/L were 54 and 57%, respectively, among those older than 70 yr with a tobacco consumption above 15 g/d and an FEV(1)% predicted of less than 50. CONCLUSIONS: CRP is a strong and independent predictor of future COPD outcomes in individuals with airway obstruction.

Aged↗

Elevated matrix metalloproteinase-9 associated with stroke or cardiovascular death in patients with carotid stenosis.

BACKGROUND: Matrix metalloproteinase-9 could exhibit an important role in the destabilization of atherosclerotic carotid plaques. We hypothesized that in patients with carotid stenosis, elevated levels of plasma matrix metalloproteinase-9 are associated with ipsilateral stroke or cardiovascular death. METHODS AND RESULTS: We followed up 207 patients with > or = 50% carotid stenosis initially for a mean of 4.4 years, during which time 53 patients developed ipsilateral stroke or died of cardiovascular causes. The cumulative incidence of ipsilateral stroke or cardiovascular death was higher in those with matrix metalloproteinase-9 above versus below the median of 41.9 ng/mL (log-rank P=0.002). Matrix metalloproteinase-9 above versus below the median had a hazard ratio for ipsilateral stroke or cardiovascular death of 1.9 (95% confidence interval [CI], 1.1 to 3.5); during extended follow-up, this remained significant until 10 years. The absolute risk of ipsilateral stroke or cardiovascular death at 4.4 years was 34% and 17% in those with matrix metalloproteinase-9 above and below the median, respectively. Elevated matrix metalloproteinase-9 and an echolucent plaque on B-mode ultrasound versus a low matrix metalloproteinase-9 and an echorich plaque had a hazard ratio for ipsilateral stroke or cardiovascular death of 4.4 (95% CI, 1.8 to 11.1) and for ipsilateral stroke of 3.3 (95% CI, 1.1 to 9.7). CONCLUSIONS: Elevated levels of matrix metalloproteinase-9 in patients with > or = 50% carotid stenosis were associated with a 2-fold risk of ipsilateral stroke or cardiovascular death. Combining elevated matrix metalloproteinase-9 and plaque echolucency was associated with a 4-fold risk for ipsilateral stroke or cardiovascular death and a 3-fold risk for ipsilateral stroke.

Aged↗

Subsets of SNPs define rare genotype classes that predict ischemic heart disease.

Single nucleotide polymorphisms (SNPs) are hypothesized to explain the genetic predisposition to ischemic heart disease (IHD) in the general population. Lack of evidence for a role of such variation is fostering pessimism about the utility of genetic information in the practice of medicine. In this study we determined the utility of exonic and 5' SNPs in apolipoprotein E (APOE) and lipoprotein lipase (LPL) when considered singly and in combination for predicting incidence of IHD in 8,456 individuals from the general population during 24 years of follow-up. In men, LPL D9N improved prediction of IHD (P = 0.03) beyond smoking, diabetes and hypertension. The group of men heterozygous and homozygous for the rare D9N variant had a hazard ratio (HR) of 1.69 (95% confidence interval = 1.10-2.58) relative to the most common genotype. Pairwise combinations of D9N with -219G > T in APOE and N291S and S447X in LPL significantly improved the prediction of IHD (P = 0.05 in women, P = 0.04 in men, P = 0.03 in men, respectively) beyond smoking, diabetes and hypertension, and identified subgroups of individuals (n = 6-94) with highly significant HRs of 1.92-4.35. These results were validated in a case-control study (n = 8,806). In conclusion, we present evidence that combinations of SNPs in APOE and LPL identify subgroups of individuals at substantially increased risk of IHD beyond that associated with smoking, diabetes and hypertension.

Adult↗

Zinc Finger Protein 202, genetic variation, and HDL cholesterol in the general population.

Zinc Finger Protein 202 (ZNF202) is a transcriptional repressor that binds elements found predominantly in genes involved in HDL metabolism. We tested the following hypotheses: 1) frequencies of single-nucleotide polymorphisms (SNPs) and haplotypes in ZNF202 differ between individuals with low and high HDL cholesterol; and 2) SNPs in ZNF202 affect HDL cholesterol levels in the general population. We screened the promoter and protein-coding exons of ZNF202 in individuals with the highest 1% (n = 95) and lowest 1% (n = 95) HDL cholesterol among 9,259 Danish adults. None of the 10 SNPs identified differed in frequency as single sites or as haplotypes between low and high HDL cholesterol groups. In accordance with this, seven mutations were equally frequent (4-5%) in individuals with low or high HDL cholesterol. Finally, for all five SNPs identified in the coding region, we determined the association of genotype with HDL cholesterol in 9,259 individuals from the general population. Four SNPs were not associated with variation in HDL cholesterol, although c.*2T>G homozygosity was associated with a discrete effect on HDL cholesterol in men. We show that genetic variation in ZNF202 is common in the general population. However, SNPs in the protein-coding region of ZNF202 do not make a major contribution to HDL cholesterol levels.

Adult↗

Combined analysis of six lipoprotein lipase genetic variants on triglycerides, high-density lipoprotein, and ischemic heart disease: cross-sectional, prospective, and case-control studies from the Copenhagen City Heart Study.

CONTEXT: Genetic variants in lipoprotein lipase may affect triglycerides, high-density lipoprotein (HDL), and risk of ischemic heart disease (IHD). OBJECTIVE: The objective of this study was to investigate the influence of T(-93)G, G(-53)C, Asp9Asn, Gly188Glu, Asn291Ser, and Ser447Ter lipoprotein lipase genotypes on triglycerides, HDL, and IHD. DESIGN: The cross-sectional study involved 9004 adults. The prospective study consisted of 8817 adults developing 1001 IHD events over 23 yr. The case-control study involved 7818 non-IHD individuals vs. cohorts of 915 and 1062 IHD patients, respectively. SETTING: The study was performed in the Danish general population (the Copenhagen City Heart Study). PARTICIPANTS: IHD was angina pectoris or myocardial infarction. MAIN OUTCOME MEASURES: Triglycerides, HDL, and IHD were the main outcome measures. RESULTS: Cross-sectionally, triglycerides varied by genotype with 1.27 mmol/liter in women and 1.22 mmol/liter in men. HDL cholesterol varied by genotype with 0.49 mmol/liter in women and 0.60 mmol/liter in men. Prospectively, 9Asn (with -93G) heterozygotes and homozygotes combined vs. noncarriers had a hazard ratio for IHD of 1.6 [95% confidence interval (CI), 1.2-2.3]; 291Ser and 447Ter did not change IHD risk. In the case-control study, combining the cohorts of IHD patients, 9Asn (with -93G) heterozygotes and homozygotes combined vs. noncarriers had an odds ratio for IHD of 1.5 (CI, 1.2-2.1). 291Ser and 447Ter did not change IHD risk. Stratified for apolipoprotein E genotype, the odds ratios for IHD in 9Asn (with -93G) heterozygotes and homozygotes combined vs. noncarriers were 2.6 (CI, 1.2-5.5) among epsilon32 individuals and 2.4 (CI, 1.4-4.1) among epsilon43 individuals. CONCLUSIONS: Genetic variation in lipoprotein lipase is associated with differences in plasma triglycerides greater than 1 mmol/liter and differences in HDL cholesterol greater than 0.5 mmol/liter. A 1.6-fold risk of IHD in 9Asn (with -93G) heterozygotes and homozygotes combined is influenced by apolipoprotein E genotype.

Adult↗

Genetically increased antioxidative protection and decreased chronic obstructive pulmonary disease.

RATIONALE: Increased oxidative stress is involved in chronic obstructive pulmonary disease (COPD); however, plasma and bronchial lining fluid contains the antioxidant extracellular superoxide dismutase. Approximately 2% of white individuals carry the R213G polymorphism in the gene encoding extracellular superoxide dismutase, which increases plasma extracellular superoxide dismutase 10-fold and presumably also renders bronchial lining fluid high in extracellular superoxide dismutase. OBJECTIVE: We tested the hypothesis that R213G reduces the risk of COPD. METHODS: We studied cross-sectionally and prospectively (during 24 yr) 9,258 individuals from the Danish general population genotyped for R213G. MEASUREMENTS: We determined plasma extracellular superoxide dismutase concentration, pulmonary function and COPD diagnosed by means of spirometry or through national hospitalization and death registers. MAIN RESULTS: In the general population, 97.5% were noncarriers, 2.4% were heterozygotes, and 0.02% were homozygotes. Among R213G noncarriers, extracellular superoxide dismutase plasma concentration was 148+/-52 and 142+/-43 ng/ml (mean+/-SD) in individuals with and without COPD (Student's t test, p=0.02). Among heterozygotes, corresponding concentrations were 1,665+/-498 ng/ml and 1,256+/-379 (p<0.001). The adjusted odds ratio for spirometrically diagnosed COPD in heterozygotes versus noncarriers was 0.5 (95% confidence interval: 0.3-0.9). After stratification, the equivalent adjusted odds ratio was 1.5 (0.3-6.6) among nonsmokers and 0.4 (0.2-0.8) among smokers (p value for interaction=0.10). The adjusted hazard ratio for COPD hospitalization or death during follow-up in heterozygotes versus noncarriers was 0.3 (0.1-0.8). CONCLUSIONS: Extracellular superoxide dismutase R213G heterozygosity protects against development of COPD in the Danish general population. This was observed in smokers, but not in nonsmokers.

Aged↗

Body mass, fat-free body mass, and prognosis in patients with chronic obstructive pulmonary disease from a random population sample: findings from the Copenhagen City Heart Study.

RATIONALE: Low body mass index (BMI) is a marker of poor prognosis in chronic obstructive pulmonary disease (COPD). In the general population, the harmful effect of low BMI is due to the deleterious effects of a low fat-free mass index (FFMI; fat-free mass/weight(2)). OBJECTIVES: We explored distribution of low FFMI and its association with prognosis in a population-based cohort of patients with COPD. METHODS: We used data on 1,898 patients with COPD identified in a population-based epidemiologic study in Copenhagen. FFM was measured using bioelectrical impedance analysis. Patients were followed up for a mean of 7 yr and the association between BMI and FFMI and mortality was examined taking age, sex, smoking, and lung function into account. MAIN RESULTS: The mean FFMI was 16.0 kg/m(2) for women and 18.7 kg/m(2) for men. Among subjects with normal BMI, 26.1% had an FFMI lower than the lowest 10th percentile of the general population. BMI and FFMI were significant predictors of mortality, independent of relevant covariates. Being in the lowest 10th percentile of the general population for FFMI was associated with a hazard ratio of 1.5 (95% confidence interval, 1.2-1.8) for overall mortality and 2.4 (1.4-4.0) for COPD-related mortality. FFMI was also a predictor of overall mortality when analyses were restricted to subjects with normal BMI. CONCLUSIONS: FFMI provides information in addition to BMI and assessment of FFM should be considered in the routine assessment of COPD.

Adiposity↗

Zinc Finger Protein 202: a new candidate gene for ischemic heart disease: The Copenhagen City Heart Study.

OBJECTIVE: Zinc Finger Protein 202 (ZNF202) is a transcriptional repressor of genes affecting the vascular endothelium as well as lipid metabolism. A phenotype associated with genetic variation in ZNF202 is presently unknown. We tested the hypothesis that a common variant in ZNF202, A154V, predicts risk of ischemic heart disease (IHD), myocardial infarction (MI), and ischemic cerebrovascular disease (ICVD). METHODS AND RESULTS: We conducted a prospective study of more than 9000 individuals from the general population with 24 years follow-up. In women, age-adjusted hazard ratios in heterozygotes and homozygotes versus non-carriers were 1.2 (95% CI: 1.0-1.5, P = 0.04) and 1.5 (1.1-2.1, P = 0.007) for IHD, 1.5 (1.1-2.1; P = 0.01) and 1.7 (1.1-2.8, P = 0.02) for MI, and 1.3 (1.0-1.8, P = 0.07) and 1.3 (0.8-2.1; P = 0.33) for ICVD. Adjustments for lipids and lipoproteins did not alter these hazard ratios substantially. Genotype did not predict risk in men. Finally, results for IHD were borderline significant (P = 0.06) in an independent case-control study including 933 patients and 8068 controls. CONCLUSION: This is the first study to suggest that ZNF202 could be a new candidate gene for IHD and MI in the general population.

Carrier Proteins↗

Ankle brachial index, C-reactive protein, and central augmentation index to identify individuals with severe atherosclerosis.

OBJECTIVES: We examined the ability of ankle brachial index, C-reactive protein and central augmentation index to identify individuals in the general population with severe atherosclerosis, diagnosed as those with ischaemic cardiovascular disease. METHODS AND RESULTS: We examined 4159 randomly sampled individuals from the Danish general population, of which 250 had severe atherosclerosis. After adjustment for gender and age, individuals with ankle brachial index of 0.71-0.90 and <0.70 vs. 0.91-1.10 had odds ratios for severe atherosclerosis of 1.6 (95%CI:1.1-2.3) and 2.9 (1.9-4.6), respectively. C-reactive protein of >3.0 or 1.0-3.0 mg/L vs. <1.0 mg/L as well as central augmentation index in quintiles did not identify individuals with severe atherosclerosis, and did not improve further the ability of ankle brachial index to identify such individuals. On a continuous scale using receiver operating characteristics curves, presence of severe atherosclerosis was predicted by ankle brachial index (P=0.00000003), C-reactive protein (P=0.000003), as well as central augmentation index (P=0.001); these three curves did not differ. CONCLUSION: Ankle brachial index <0.9 identify individuals with severe atherosclerosis in the general population, while C-reactive protein in three groups and central augmentation index in quintiles did not. On a continuous scale, all three variables predicted severe atherosclerosis.

Adult↗

Asthma and COPD in cystic fibrosis intron-8 5T carriers. A population-based study.

BACKGROUND: Carriers of cystic fibrosis intron-8 5T alleles with high exon-9 skipping could have increased annual lung function decline and increased risk for asthma or chronic obstructive pulmonary disease (COPD). METHODS: We genotyped 9131 individuals from the adult Danish population for cystic fibrosis 5T, 7T, 9T, and F508del alleles, and examined associations between 11 different genotype combinations, and annual FEV1 decline and risk of asthma or COPD. RESULTS: 5T heterozygotes vs. 7T homozygous controls had no increase in annual FEV1 decline, self-reported asthma, spirometry-defined COPD, or incidence of hospitalization from asthma or COPD. In 5T/7T heterozygotes vs. 7T homozygous controls we had 90% power to detect an increase in FEV1 decline of 8 ml, an odds ratio for self-reported asthma and spirometry-defined COPD of 1.9 and 1.7, and a hazard ratio for asthma and COPD hospitalization of 1.8 and 1.6, respectively. Both 5T homozygotes identified in the study showed evidence of asthma, while none of four 5T/F508del compound heterozygotes had severe pulmonary disease. 7T/9T individuals had annual decline in FEV1 of 19 ml compared with 21 ml in 7T homozygous controls (t-test: P = 0.03). 6.7% of 7T homozygotes without an F508del allele in the cystic fibrosis transmembrane conductance regulator gene reported asthma vs. 11% of 7T/9T individuals with an F508del allele (chi2: P = 0.01) and 40% of 7T homozygotes with an F508del allele (P = 0.04). 7T homozygotes with vs. without an F508del allele also had higher incidence of asthma hospitalization (log-rank: P = 0.003); unadjusted and adjusted equivalent hazard ratios for asthma hospitalization were 11 (95%CI: 1.5-78) and 6.3 (0.84-47) in 7T homozygotes with vs. without an F508del allele. CONCLUSION: Polythymidine 5T heterozygosity is not associated with pulmonary dysfunction or disease in the adult Caucasian population. Furthermore, our results support that F508del heterozygosity is associated with increased asthma risk independently of the 5T allele.

Adult↗

Factor V leiden homozygosity, dyspnea, and reduced pulmonary function.

BACKGROUND: Factor V Leiden homozygosity predisposes patients to deep venous thrombosis and major pulmonary thromboembolism. Consequently, factor V Leiden homozygosity could, via unrecognized repeated minor pulmonary thromboemboli, cause chronic pulmonary disease. We tested the hypothesis that factor V Leiden homozygosity is associated with pulmonary symptoms and signs. METHODS: We studied a general population sample of 9253 individuals from the Copenhagen City Heart Study who were examined in 1991-1994. Of these, 6475 participants were also examined in 1976-1978 and/or 1981-1983. End points were dyspnea and lung function. RESULTS: Among 20 factor V Leiden homozygotes, a mean +/- SD of 32% +/- 11% had severe dyspnea compared with 6% +/- 0.3% of 8534 noncarriers (chi(2) test; P<.001). The corresponding adjusted odds ratio for severe dyspnea was 5.4 (95% confidence interval, 1.9-15.7). During follow-up, forced expiratory volume in 1 second and forced vital capacity were 5% to 10% lower in homozygotes vs noncarriers (analysis of variance; P = .003 and P = .03). The annual mean +/- SD loss of forced expiratory volume in 1 second and forced vital capacity was 39 +/- 8 mL/y and 35 +/- 8 mL/y in homozygotes vs 21 +/- 10 mL/y and 15 +/- 10 mL/y in noncarriers (t test; P = .03 and P = .04), respectively. Factor V Leiden heterozygosity (n = 699) did not influence pulmonary symptoms and signs. CONCLUSION: We demonstrate a previously unrecognized clinical presentation of factor V Leiden homozygosity with severe dyspnea and decreased pulmonary function.

Adult↗

Mutation in ABCA1 predicted risk of ischemic heart disease in the Copenhagen City Heart Study Population.

OBJECTIVES: We tested whether heterozygosity for the K776N mutation (frequency: 0.4%) in ATP-binding cassette transporter A1 (ABCA1) predicted ischemic heart disease (IHD) in the Copenhagen City Heart Study population. BACKGROUND: In a complex trait like IHD, genetic variation is considered to be conferred by common DNA polymorphisms, although rare mutations may have a larger impact. Tangier disease, a rare high-density lipoprotein cholesterol (HDL-C) deficiency syndrome with IHD, is caused by homozygous ABCA1 mutations. METHODS: We analyzed blood samples from a large cohort study of 9,076 Danish individuals followed for 24 years (167,287 person-years), during which 1,033 incident IHD events occurred. The hypothesis was retested in an independent case-control study comparing 562 IHD patients with 3,103 controls. RESULTS: The cumulative incidence of IHD as a function of age was increased in K776N heterozygotes compared with non-carriers (log-rank test: p = 0.005). At the age of 80 years, 48% of heterozygotes and 23% of non-carriers had IHD. Incidence rates in non-carriers and K776N heterozygotes were 61 and 157 per 10,000 person-years. The age-adjusted hazard ratio for IHD in K776N heterozygotes versus non-carriers was 2.4 (95% confidence interval 1.3 to 4.5). Adjusting for HDL-C, or for smoking, diabetes, and hypertension did not change the result, suggesting that genotype predicted risk of IHD beyond that offered by HDL-C, and by other conventional risk factors. Similar trends were obtained in an independent case-control study. CONCLUSIONS: Heterozygosity for an ABCA1 mutation (K776N) conferred two- to three-fold risk of IHD in 37 participants in the Copenhagen City Heart study.

ATP Binding Cassette Transporter 1↗

Polymorphism in APOB associated with increased low-density lipoprotein levels in both genders in the general population.

CONTEXT: Rare mutations in APOB cause hypercholesterolemia. Whether common polymorphisms in APOB have similar effects remains controversial. OBJECTIVE: We tested the hypothesis that the APOB 7673C>T polymorphism (T2488T) is associated with variation in low-density lipoprotein (LDL) levels and with risk of ischemic heart disease (IHD), ischemic cerebrovascular disease (ICVD), and total mortality in the general population. DESIGN: The design was a cohort study with 22-yr follow-up (166,232 person years) and two case-control studies, The Copenhagen City Heart Study. SETTINGS: The study was performed within the Danish general population and at a university hospital. PARTICIPANTS: The study was comprised of 9185 individuals from the general population, 2157 patients with IHD, and 378 patients with ICVD. MAIN OUTCOME MEASURES: The main outcome measures were lipids, lipoproteins, apolipoproteins (apo), IHD, ICVD, and total mortality. RESULTS: Genotype was associated with increases in total cholesterol (women/men), LDL cholesterol, and apoB of 0.20/0.26 mmol/liter (3.3%/4.4%), 0.22/0.28 mmol/liter (5.9%/7.8%), and 5.0/5.6 mg/dl (5.9%/6.7%) in TT vs. CC homozygotes, respectively. These results were consistent over time. Despite this, the 7673C>T polymorphism was not associated with risk of IHD, ICVD, or total mortality prospectively or in case-control studies. CONCLUSION: The APOB 7673C>T polymorphism is associated with moderate increases in total cholesterol, LDL cholesterol, and apoB in both genders in the general population, but not with risk of IHD, ICVD, or total mortality.

Adult↗

Hereditary hemochromatosis and risk of ischemic heart disease: a prospective study and a case-control study.

BACKGROUND: We tested the hypothesis that the hereditary hemochromatosis genotypes C282Y/C282Y, C282Y/H63D, or C282Y/wild-type are risk factors for ischemic heart disease (IHD) and myocardial infarction (MI). METHODS AND RESULTS: We performed a prospective study of 9178 individuals from the Danish general population followed up for 24 years, during which 1035 and 511 developed IHD and MI, respectively, and a case-control study of 2441 and 1113 IHD and MI cases versus 8080 controls. C282Y/C282Y, C282Y/H63D, and C282Y/wild-type versus wild-type/wild-type individuals were not associated with increased risk of IHD or MI in prospective studies, overall or stratified by gender. We had 90% power to detect a hazard ratio for IHD of 3.4 for C282Y/C282Y, 1.9 for C282Y/H63D, and 1.3 for C282Y/wild-type versus wild-type/wild-type. Furthermore, these genotypes were not associated with increased risk of IHD or MI in case-control studies, overall or stratified by gender. We had 90% power to detect an odds ratio for IHD of 3.6 for C282Y/C282Y, 1.8 for C282Y/H63D, and 1.3 for C282Y/wild-type versus wild-type/wild-type. CONCLUSIONS: In these studies, hereditary hemochromatosis C282Y/C282Y, C282Y/H63D, and C282Y/wild-type genotypes were not associated with IHD or MI; however, the study lacked the power to exclude the possibility that C282Y/C282Y and C282Y/H63D individuals have a modestly increased risk of IHD or MI.

Adult↗

Mutation in apolipoprotein B associated with hypobetalipoproteinemia despite decreased binding to the low density lipoprotein receptor.

Mutations in apolipoprotein B (APOB) may reduce binding of low density lipoprotein (LDL) to the LDL receptor and cause hypercholesterolemia. We showed that heterozygotes for a new mutation in APOB have hypobetalipoproteinemia, despite a reduced binding of LDL to the LDL receptor. APOB R3480P heterozygotes were identified among 9,255 individuals from the general population and had reduced levels of apoB-containing lipoproteins. Most surprisingly, R3480P LDL bound with lower affinity to the LDL receptor than non-carrier LDL in vitro, and these results were confirmed by turnover studies of LDL in vivo. In very low density lipoprotein (VLDL) turnover studies, the amount of VLDL converted to LDL in R3480P heterozygotes was substantially reduced, suggesting that this was the explanation for the hypobetalipoproteinemia observed in these individuals. Our findings emphasized the importance of combining in vitro studies with both human in vivo and population-based studies, as in vitro studies often have focused on very limited aspects of complex mechanisms taken out of their natural context.

Adult↗

The penetrance of hereditary hemochromatosis.

Since its original description as a rare disease of iron overload resulting in liver disease, diabetes mellitus, and bronzing of the skin ('bronze diabetes'), hereditary hemochromatosis has undergone several redefinitions leading to widely varying estimates of its prevalence. Over the last decade, the finding of a relatively high prevalence of the C282Y polymorphism of the HFE gene associated with hemochromatosis in Northern European populations suggested that the disease may be much more common than previously thought. However, several large population-based studies have now shown that the penetrance of the C282Y/C282Y genotype is very low, indicating that C282Y homozygosity is a necessary but not sufficient factor in causation of the disease. Studies are now focusing on other genetic and environmental factors, including alcohol, that may contribute to differential expression of C282Y homozygosity.

Age Factors↗

164Ile allele in the beta2-Adrenergic receptor gene is associated with risk of elevated blood pressure in women. The Copenhagen City Heart Study.

OBJECTIVE: Since beta2-adrenergic receptors are important regulators of blood pressure, genetic variation in this receptor could explain risk of elevated blood pressure in selected individuals. We tested the hypothesis that Gly16Arg, Gln27Glu, and Thr164Ile in the beta2-adrenergic receptor gene associated with elevated blood pressure. METHODS: We genotyped 9185 individuals from the adult Danish general population. RESULTS: Allele frequencies of 16Arg, 27Glu, and 164Ile were 0.38, 0.44, and 0.01, respectively. Among women never treated with antihypertensive medication those heterozygous for Thr164Ile versus non-carriers had increased diastolic blood pressure (P=0.02). Women heterozygous for Thr164Ile versus non-carriers had an odds ratio for elevated blood pressure of 1.93 (95% CI: 1.30-2.86). Finally, women double heterozygous for Thr164Ile and Gln27Glu or Gly16Arg versus non-carriers at all 3 loci had an odds ratio for elevated blood pressure of 2.49 (1.28-4.85) or 3.19 (1.46-6.97). In men, blood pressure was not influenced by this genetic variation. CONCLUSION: In women Thr164Ile heterozygosity is associated with increased diastolic blood pressure, and represent a risk factor for elevated blood pressure in women in the general population. This was most pronounced in those women also heterozygous for Gln27Glu or Gly16Arg.

Alleles↗