| 431. |
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| 432. |
- Leu, Monica, 1977, et al.
(författare)
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Bias and bias-correction of estimates of familial risk in population-based register
- 2009
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Ingår i: International Journal of Epidemiology. - 0300-5771. ; 39:1, s. 80-8
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Tidskriftsartikel (refereegranskat)abstract
- Background In addition to guiding molecular epidemiology investigations, estimates of the increased risk of disease in relatives of affected persons are also important for screening and counselling decisions. Since precise estimation of such familial risks (FRs) requires large sample sizes, many of the estimates in common use have been obtained from historical electronic records of disease in entire populations, where the relatives of affected and unaffected persons are compared. These estimates may be biased due to failure to identify relatives as affected if they are diagnosed before the start-up date of disease registration. Methods This article presents a method for correcting the bias in FR estimates from such misclassification of family history, using a simple formula that depends on the prevalence and sensitivity of the observed family history. The sensitivity is estimated by using the R package poplab to create realistic populations of related individuals and then imposing the start-up effect of disease registration. Results For a range of FRs, the truncation of family history is demonstrated to result in non-differential misclassification, and sensitivity that has little or no dependence on the FR. The bias is most pronounced for high FRs and for registers with a short life span, and increases with the age of the study cohort. In all the situations studied, the bias-corrected estimates are in excellent agreement with the true values. Conclusions In summary, our method can correct the inevitable bias in FRs induced by using electronic population data, and is a feasible alternative to the use of validation samples.
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| 433. |
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| 434. |
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| 435. |
- Lindberg, Gunnar, et al.
(författare)
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Serum sialic acid and its correlates in community samples from Akita, Japan and Minneapolis, USA
- 1997
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Ingår i: International Journal of Epidemiology. - 1464-3685. ; 26:1, s. 58-63
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The concentration of serum total sialic acid (S-TSA) is one recently investigated risk marker for cardiovascular mortality and atherosclerosis. Since the mortality from coronary heart disease is higher in the United States than in Japan, one could expect the S-TSA to be higher among Caucasian US citizens than among Japanese citizens, a hypothesis that is tested in this study. DESIGN: Cross-sectional study of population-based samples of Japanese and US Caucasian men and women. SETTING: The rural community Akita, Japan, and the suburbs of Minneapolis, Minnesota. SUBJECTS: These were 75 consecutive men and women from Akita and Minneapolis respectively aged 47-69 years in 1990. People who had smoked cigarettes during the past 5 years; who had a history of diabetes mellitus, liver disease, coronary heart disease, or stroke; or who were taking anticoagulants were excluded. OUTCOME MEASURES: Serum total sialic acid levels in male and female Japanese and US Caucasian subjects with adjustment for age, systolic blood pressure, fibrinogen, triglycerides and in women also for menopausal status. Race and sex-specific correlations with serum total sialic acid for selected cardiovascular risk markers. RESULTS: The entire sialic acid distributions were shifted to the right in Caucasian men and women compared to Japanese men and women. The mean +/- standard deviation concentrations of S-TSA were 54.1 +/- 5.3 mg/dl in Japanese men and 58.7 +/- 5.6 mg/dl in Caucasian men (P < 0.001). In women, the concentrations were 54.8 +/- 5.1 and 63.1 +/- 6.0 mg/dl respectively (P < 0.001). S-TSA level correlated significantly and positively with fibrinogen levels in Caucasian and Japanese men and women and with triglyceride levels in Caucasian and Japanese men and in Caucasian women but not in Japanese women. After adjustment for age, systolic blood pressure, fibrinogen, triglycerides and menopausal status, the sialic acid levels were 2.2 (P = 0.009) and 6.2 (P < 0.001) mg/dl higher in Caucasian compared to Japanese men and women respectively. CONCLUSIONS: Higher S-TSA levels in Caucasians living in Minneapolis compared to Japanese living in Akita, Japan is in concordance with the higher cardiovascular mortality in the US. Differences in S-TSA levels may reflect international differences in the prevalence of atherosclerosis.
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| 436. |
- Lindberg, Gunnar, et al.
(författare)
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The association between serum sialic acid and asymptomatic carotid atherosclerosis is not related to antibodies to herpes type viruses or Chlamydia pneumoniae. The Atherosclerosis Risk in Communities (ARIC) Study Investigators
- 1997
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Ingår i: International Journal of Epidemiology. - 1464-3685. ; 26:6, s. 1386-1391
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Total serum sialic acid is a recently investigated marker for cardiovascular mortality and carotid atherosclerosis. This study tested the hypothesis that past infection by Herpes simplex type 1 or type 2 viruses or Cytomegalovirus or Chlamydia pneumoniae accounts for the association between serum total sialic acid and atherosclerosis. METHODS: Population-based samples of men and women living in four US communities were used in a cross-sectional study. Cases and matched controls were defined by B-mode ultrasound measurements of carotid and popliteal arterial wall thickness. In all, there were 267 case control pairs with information about antibody titres to viruses and 256 pairs with information about antibody titres to Chlamydia pneumoniae. RESULTS: Serum total sialic acid (S-TSA) level was significantly higher in cases with carotid atherosclerosis compared to their controls. The odds ratio for carotid atherosclerosis associated with sialic acid level above 75th percentile was 1.73 (95% confidence interval [CI]: 1.02-2.95) in the sample with information about antibodies to viruses and 1.70 (95% CI: 1.00-2.93) in the sample with information about antibodies to C. pneumoniae. Adjustment for titres of antibodies to viruses and C. pneumoniae had no impact on the relation between sialic acid and carotid atherosclerosis. CONCLUSIONS: From these results, it seems unlikely that previous infection by any of these micro-organisms accounts for the relation between S-TSA level and carotid atherosclerosis.
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| 437. |
- Lindström, Martin, et al.
(författare)
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Socioeconomic differences in fat intake in a middle-aged population: report from the Malmö Diet and Cancer Study
- 2000
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Ingår i: International Journal of Epidemiology. - : Oxford University Press (OUP). - 1464-3685. ; 29:3, s. 438-448
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Tidskriftsartikel (refereegranskat)abstract
- Background: The objective was to investigate whether socioeconomic differences in fat intake may explain socioeconomic differences in cardiovascular diseases. Methods: The Malm Diet and Cancer Study is a prospective cohort study. The baseline examinations used in the present cross-sectional study were undertaken in 19921994. Dietary habits were assessed using a modified diet history method consisting of a 7-day menu book and a 168-item questionnaire. A subpopulation of 11 837 individuals born 19261945 was investigated. This study examined high fat intake, defined as >35.9 among men and >34.8 among women (25 quartile limit) of the proportion of the non-alcohol energy intake contributed by fat. The subfractions saturated, mono-unsaturated and poly-unsaturated fatty acids and the P:S ratio (polyunsaturated/saturated fatty acids) were analysed in the same way. The uppermost quartile (75) of total and subgroup fat intake was also studied. Socioeconomic differences before and after adjustment for low energy reporting (LER), defined as energy intake below 1.2 x Basal Metabolic Rate, were examined. Results: No socioeconomic differences in fat intake were seen between the SES groups, except for self-employed men, and male and female pensioners. Approximately 20 in most SES groups were LER. The LER and body mass index were strongly related. The SES pattern of fat intake remained unchanged after adjustment for age, country of origin and LER in a logistic regression model. The results for the subfractions of fat and the P:S ratio did not principally differ from the total fat results. Conclusions: This study provides no evidence that fat intake contributes to the inverse socioeconomic differences in cardiovascular diseases.
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| 438. |
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| 439. |
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