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Biomedical subjects

Anne Tybjaerg-Hansen

Publications and source records attributed to Anne Tybjaerg-Hansen.

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↗

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↗

Increased risk of breast cancer associated with CHEK2*1100delC.

PURPOSE: CHEK2*1100delC heterozygosity has been associated with increased risk of breast, prostate, and colorectal cancer in case-control studies. We tested the hypothesis that CHEK2*1100delC heterozygosity in the general population increases the risk of cancer in general, and breast, prostate, and colorectal cancer in particular. PATIENTS AND METHODS: We performed a prospective study of 9,231 individuals from the Danish general population, who were observed for 34 years, and we performed a case-control study including 1,101 cases of breast cancer and 4,665 controls. RESULTS: Of the general population, 0.5% were heterozygotes and 99.5% were noncarriers. In the prospective study, multifactorially adjusted hazard ratios by CHEK2*1100delC heterozygosity versus noncarriers were 1.2 (95% CI, 0.7 to 2.1) for all cancers, 3.2 (95% CI, 1.0 to 9.9) for breast cancer, 2.3 (95% CI, 0.6 to 9.5) for prostate cancer, and 1.6 (95% CI, 0.4 to 6.5) for colorectal cancer. In the case-control study, age-matched odds ratio for breast cancer by CHEK2*1100delC heterozygosity versus noncarriers was 2.6 (95% CI, 1.3 to 5.4). The absolute 10-year risk of breast cancer in CHEK2*1100delC heterozygotes amounted to 24% in women older than 60 years undergoing hormone replacement therapy, with a body mass index of 25 kg/m2 or higher. CONCLUSION: CHEK2*1100delC heterozygosity is associated with a three-fold risk of breast cancer in women in the general population.

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↗

Contribution of regulatory and structural variations in APOE to predicting dyslipidemia.

The objective of this study was to evaluate 1) whether non single nucleotide polymorphisms-coding (non-cSNP) in the apolipoprotein E gene (APOE) identified by resequencing studies contribute to statistically explaining dyslipidemia if variations in the two cSNPs in exon 4 that define the 2, 3, and 4 alleles are ignored, and 2) whether the contribution of these additional SNPs persists when variations in the cSNPs are considered. We used an ecological, multiple-population, data-mining strategy to identify single-SNP and two-SNP genotypes that distinguish between high and low levels of plasma lipids in three training samples, European-Americans from Rochester, MN, African-Americans from Jackson, MS, and Europeans from North Karelia, Finland. We found that a pair of SNPs located in the 5' region define genotypes A560T832/A560T832, A560T832/A560G832, and A560T832/T560T832, which distinguish between high and low levels of HDL-cholesterol (HDL-C), triglycerides (TG), and/or total cholesterol (T-C). The A560T832/- genotypes predicted high TG and high T-C in both genders in a large independent test sample from Copenhagen, Denmark. Prediction of high T-C in the Danish females was dependent on genotypes defined by the cSNPs. Our study suggests that both regulatory and structural variations should be considered when evaluating the utility of APOE for predicting dyslipidemia in the population at large.

Black or African American↗

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↗

Promoter haplotype of a new ABCA1 mutant influences expression of familial hypoalphalipoproteinemia.

Mutations in the ATP-binding cassette A1 (ABCA1) transporter cause the high-density lipoprotein (HDL) deficiency syndromes of Tangier disease and familial hypoalphalipoproteinemia (FHA). Between individuals carrying ABCA1 mutations, the expression of FHA can be highly variable. Using denaturing HPLC (dHPLC) and direct promoter sequencing we screened the ABCA1 gene of a family with Tangier disease and variable expression of FHA. A new mutation (R1068H) within the first ATP-binding domain was identified in homozygous form in the Tangier disease individual and was present in several family members. Haplotyping of both 1068H alleles in the proband showed homozygosity in the coding region, however, the maternal 1068H allele had three single nucleotide polymorphisms (SNPs) in the promoter previously reported to be associated with reduced ABCA1 expression and HDL levels. An analysis of HDL levels based on 1068H allele haplotype showed the paternal 1068H heterozygotes to have the expected low HDL levels (0.67+/-0.16mmol/L), while maternal 1068H heterozygotes showed normal HDL levels (1.18+/-0.14mmol/L). Haplotype analysis of the wildtype allele amongst heterozygotes showed no haplotype that was common to the paternal or maternal side. We propose that the paternal 1068H ABCA1 allele causes a negative effect on the function of the wildtype allele and is associated with low HDL levels. In contrast, the maternal 1068H allele has less effect and is associated with a relatively normal HDL level. We conclude that haplotypes of mutant ABCA1 alleles may contribute to the phenotypic variance shown between FHA individuals.

ATP Binding Cassette Transporter 1↗

Influence of the factor V Leiden mutation on infectious disease susceptibility and outcome: a population-based study.

BACKGROUND: The effect of the coagulation factor V Leiden mutation on infectious disease susceptibility and outcome is controversial. METHODS: We genotyped 9253 individuals from the Copenhagen City Heart Study for the factor V Leiden mutation. The risk of hospitalization for any infectious disease during a follow-up period of 7.2 years and subsequent risk of disease progression to death were estimated by Cox proportional-hazards regression analysis. RESULTS: During 66,789 person-years of follow-up, 1093 persons were hospitalized because of infection. The risk of urinary-tract infection was decreased in factor V Leiden heterozygotes, compared with that in noncarriers (adjusted relative risk [aRR], 0.55 [95% confidence interval [CI], 0.31-0.99]), whereas the risk of skin infection was increased (aRR, 1.68 [95% CI, 1.07-2.66]). No associations between carrier status and risk of diarrheal disease, other viral infections, parasitic infections, pneumonia, sepsis, or upper respiratory-tract infection were detected. However, in subjects hospitalized for sepsis, factor V Leiden carriers were at an increased risk of mortality 28 days after admission, compared with noncarriers (aRR, 4.41; 95% CI, 1.42-13.67]). CONCLUSION: In the Danish general population, the factor V Leiden mutation may be associated with infectious disease susceptibility and an increased risk of mortality from sepsis.

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↗