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1.  Usual choline and betaine dietary intake and incident coronary heart disease: the Atherosclerosis Risk in Communities (ARIC) Study 
Background
Low dietary intake of the essential nutrient choline and its metabolite betaine may increase atherogenesis both through effects on homocysteine methylation pathways as well as through choline's antioxidants properties. Nutrient values for many common foods for choline and betaine have recently become available in the U.S. nutrient composition database. Our objective was to assess the association of dietary intake of choline and betaine with incident coronary heart disease (CHD), adjusting for dietary intake measurement error.
Methods
We conducted a prospective investigation of the relation between usual intake of choline and betaine with the risk of CHD in 14,430 middle-aged men and women of the biethnic Atherosclerosis Risk in Communities study. A semi-quantitative food frequency questionnaire was used to assess nutrient intake. Proportional hazard regression models were used to calculate the risk of incident CHD. A regression calibration method was used to adjust for measurement error.
Results
During an average 14 years of follow-up (1987–2002), 1,072 incident CHD events were documented. Compared with the lowest quartile of intake, incident CHD risk was slightly and non-significantly higher in the highest quartile of choline and choline plus betaine, HR = 1.22 (0.91, 1.64) and HR = 1.14 (0.85, 1.53), controlling for age, sex, education, total energy intake, dietary intakes of folate, methionine and vitamin B6. No association was found between dietary choline intake and incident CHD when correcting for measurement error.
Conclusion
Higher intakes of choline and betaine were not protective for incident CHD. Similar investigations in other populations are of interest.
doi:10.1186/1471-2261-7-20
PMCID: PMC1934379  PMID: 17629908
2.  The association of the ankle-brachial index with incident coronary heart disease: the Atherosclerosis Risk In Communities (ARIC) study, 1987–2001 
Background
Peripheral arterial disease (PAD), defined by a low ankle-brachial index (ABI), is associated with an increased risk of cardiovascular events, but the risk of coronary heart disease (CHD) over the range of the ABI is not well characterized, nor described for African Americans.
Methods
The ABI was measured in 12186 white and African American men and women in the Atherosclerosis Risk in Communities Study in 1987–89. Fatal and non-fatal CHD events were ascertained through annual telephone contacts, surveys of hospital discharge lists and death certificate data, and clinical examinations, including electrocardiograms, every 3 years. Participants were followed for a median of 13.1 years. Age- and field-center-adjusted hazard ratios (HRs) were estimated using Cox regression models.
Results
Over a median 13.1 years follow-up, 964 fatal or non-fatal CHD events accrued. In whites, the age- and field-center-adjusted CHD hazard ratio (HR, 95% CI) for PAD (ABI<0.90) was 2.81 (1.77–4.45) for men and 2.05 (1.20–3.53) for women. In African Americans, the HR for men was 4.86 (2.76–8.47) and for women was 2.34 (1.26–4.35). The CHD risk increased exponentially with decreasing ABI as a continuous function, and continued to decline at ABI values > 1.0, in all race-gender subgroups. The association between the ABI and CHD relative risk was similar for men and women in both race groups. A 0.10 lower ABI increased the CHD hazard by 25% (95% CI 17–34%) in white men, by 20% (8–33%) in white women, by 34% (19–50%) in African American men, and by 32% (17–50%) in African American women.
Conclusion
African American members of the ARIC cohort had higher prevalences of PAD and greater risk of CHD associated with ABI-defined PAD than did white participants. Unlike in other cohorts, in ARIC the CHD risk failed to increase at high (>1.3) ABI values. We conclude that at this time high ABI values should not be routinely considered a marker for increased CVD risk in the general population. Further research is needed on the value of the ABI at specific cutpoints for risk stratification in the context of traditional risk factors.
doi:10.1186/1471-2261-7-3
PMCID: PMC1784111  PMID: 17227586
3.  The reliability of the ankle-brachial index in the Atherosclerosis Risk in Communities (ARIC) study and the NHLBI Family Heart Study (FHS) 
Background
A low ankle-brachial index (ABI) is associated with increased risk of coronary heart disease, stroke, and death. Regression model parameter estimates may be biased due to measurement error when the ABI is included as a predictor in regression models, but may be corrected if the reliability coefficient, R, is known. The R for the ABI computed from DINAMAP™ readings of the ankle and brachial SBP is not known.
Methods
A total of 119 participants in both the Atherosclerosis Risk in Communities (ARIC) study and the NHLBI Family Heart Study (FHS) had repeat ABIs taken within 1 year, using a common protocol, automated oscillometric blood pressure measurement devices, and technician pool.
Results
The estimated reliability coefficient for the ankle systolic blood pressure (SBP) was 0.68 (95% CI: 0.57, 0.77) and for the brachial SBP was 0.74 (95% CI: 0.62, 0.83). The reliability for the ABI based on single ankle and arm SBPs was 0.61 (95% CI: 0.50, 0.70) and the reliability of the ABI computed as the ratio of the average of two ankle SBPs to two arm SBPs was estimated from simulated data as 0.70.
Conclusion
These reliability estimates may be used to obtain unbiased parameter estimates if the ABI is included in regression models. Our results suggest the need for repeated measures of the ABI in clinical practice, preferably within visits and also over time, before diagnosing peripheral artery disease and before making therapeutic decisions.
doi:10.1186/1471-2261-6-7
PMCID: PMC1435775  PMID: 16504033
4.  The association of spatial T wave axis deviation with incident coronary events. The ARIC cohort 
Background
Although current evidence suggests that the spatial T wave axis captures important information about ventricular repolarization abnormalities, there are only a few and discordant epidemiologic studies addressing the ability of the spatial T wave axis to predict coronary heart disease (CHD) occurrence.
Methods
This prospective study analyzed data from 12,256 middle-aged African American and white men and women, from the Atherosclerosis Risk in Communities Study (ARIC). Following a standardized protocol, resting standard 12-lead, 10-second electrocardiograms were digitized and analyzed with the Marquette GE program. The median follow-up time was 12.1 years; incident coronary heart disease comprised fatal and non-fatal CHD events.
Results
The incidence rate of CHD was 4.26, 4.18, 4.28 and 5.62 per 1000 person-years respectively, across the spatial T wave axis quartiles. Among women for every 10 degrees increase in the spatial T wave axis deviation, there was an estimated increase in the risk of CHD of 1.16 (95% CI 1.04–1.28). After adjustment for age, height, weight, smoking, hypertension, diabetes, QRS axis and minor T wave abnormalities, this hazard rate ratio for women fell to 1.03 (0.92–1.14). The corresponding crude and adjusted hazard ratios for men were 1.05 (95% CI 0.96–1.15) and 0.95 (0.86–1.04) respectively.
Conclusions
In conclusion, this prospective, population-based, bi-ethnic study of men and women free of coronary heart disease at baseline shows that spatial T wave axis deviation is not associated with incident coronary events during long-term follow up. It is doubtful that spatial T wave axis deviation would add benefit in the prediction of CHD events above and beyond the current traditional risk factors.
doi:10.1186/1471-2261-5-2
PMCID: PMC546201  PMID: 15644132

Results 1-4 (4)