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Biomedical subjects

F J Kok

Publications and source records attributed to F J Kok.

140 records · Page 8Linked to original sources
PubMed1987

Serum selenium, vitamin antioxidants, and cardiovascular mortality: a 9-year follow-up study in the Netherlands.

The association between low serum selenium, vitamin A, and vitamin E levels and mortality from cardiovascular disease (CVD) was investigated in a case-control study nested in a 9-yr prospective study in the Netherlands. For 10,532 persons aged greater than or equal to 5 yr who participated in a 1975-1978 medical survey, serum was stored at -20 degrees C. For the 84 of 106 subjects aged 37-87 yr who died of CVD after the baseline exam, 168 cohort members alive at the end of 1983 and matched for age and gender were selected as controls. No significant associations between serum selenium. vitamin A, vitamin E, and CVD mortality were observed before and after multivariate analyses. The adjusted risk of death from CVD for subjects in the lowest selenium quintile (less than 105.0 micrograms/L) was 1.6 (95% CI, 0.8-3.2). For coronary and stroke death risk, estimates were 1.1 (95% CI, 0.5-2.6) and 3.2 (95% CI, 0.8-12.1). Our findings do not show a clear CVD risk from low selenium and vitamin levels. Although some of the risk estimates were strong, larger studies are required for definitive conclusions.

Adult↗
PubMed1987

Selenium status and chronic disease mortality: Dutch epidemiological findings.

This paper summarizes Dutch epidemiological findings on the impact of a low selenium (Se) status on mortality from cardiovascular disease (CVD) and cancer. Se status parameters of Dutch subjects are compared to those from Finland and the USA, and the concept of a threshold effect for Se on disease risk is discussed. Case-control analyses of prospective data suggest that low serum Se (below 105 micrograms/l) is not clearly associated with an excess risk of CVD death (relative risk RR = 1.6, 90% confidence interval Cl = 0.9-2.9). Se cancer findings indicate a possible gender difference in risk (in males RR = 2.7, 90% Cl = 1.2-6.2; in females RR = 1.5, 90% Cl = 0.5-4.5). Larger studies, monitoring a combination of Se status parameters are recommended.

Cardiovascular Diseases↗
PubMed1987

Is serum selenium a risk factor for cancer in men only?

The association of serum selenium with the subsequent risk of death from cancer was investigated in a case-control study that was nested in a prospective nine-year follow-up study in the Netherlands. In 1975-1978, 10,532 persons in the Dutch town of Zoetermeer who were aged five years or more participated in a medical survey. Serum samples were collected and stored at -20 C. For the 82 persons who died of cancer since the baseline examination, 164 cohort members still alive by the end of 1983 were selected as controls and matched for age, sex, and smoking. Cancer deaths that occurred in the first year of follow-up were excluded, leaving 69 cases for statistical analyses. The mean serum selenium level of 116.7 +/- 4.0 micrograms/liter among male cancer deaths (n = 40) was significantly different (p = 0.04) from that in the control subjects (126.4 +/- 3.1 micrograms/liter). In females, selenium levels were similar among cases and controls. The adjusted risk of death from cancer for men in the lowest quintile of serum selenium (below 100.8 micrograms/liter) was more than twice that of subjects with higher levels (relative risk = 2.7,90% confidence interval = 1.2-6.2). These data support recent findings of an increased cancer risk associated with low serum selenium levels in men but not in women.

Epidemiologic Methods↗
PubMed1987

Scoring of prudent dietary habits and its relation to 25-year survival.

To evaluate the effect on longevity of a diet that is concurrent with common dietary guidelines, a simple diet scoring system was developed and applied in a follow-up study of 2,820 middle-aged Dutch civil servants and their spouses. In the early 1950s those civil servants were seen for a health examination that included a dietary survey. Consumption frequency data of the quantitatively most important food items at that time were used for the diet scoring. Overall survival after 25 years was 46.8% among men and 68.6% among women. In men, a significant positive association between prudent diet score and 25-year, age-adjusted survival could be demonstrated. Of the 10 food items that constituted the diet score, a higher intake of brown bread, porridge and/or yogurt, vegetables, fish, and fruit was associated with a slightly better survival. In a separate analysis we had found a significant inverse relationship between coffee consumption and survival. A similar trend, which, however, was not significant, was observed for alcohol intake. In women, the results for the separate food items were inconsistent, and no effect of a prudent diet score on longevity was observed. The proposed diet scoring system provides a means for evaluating the effects of the individual's food choice behavior on subsequent health and longevity.

Diet↗
PubMed1986

Aortic calcification as a predictor of cardiovascular mortality.

Since aortic calcification is seen on X-rays of the prelumbar region in many patients, its relation with cardiovascular disease (CVD) was investigated in a prospective study in The Netherlands. X-rays were taken of 1359 men and 1598 women, in 1975-78. In the subsequent 9 years, 50 men and 33 women died from CVD. The prevalence of aortic calcification was about 10% in middle-aged subjects and rose with age to a maximum of 45% in men and 75% in women. Aortic calcification was associated with a six-fold increased risk of CVD death in men aged 45 years, independent of major CVD risk factors. For each year of age over 45, risk associated with the presence of aortic calcification declined by 6%. Death rates in middle-aged women were too small for risk analysis. These results suggest that atherosclerosis in other than coronary or cerebral vessels may have predictive relevance for CVD death: its diagnosis indicates intervention on present CVD risk factors.

Aged↗
PubMed1986

Dietary sodium, calcium, and potassium, and blood pressure.

The cross-sectional association of systolic blood pressure with dietary sodium, calcium, and potassium, as estimated from dietary histories, was investigated by multiple regression analysis of data gathered in the Netherlands in the early 1950s in a general health examination of 2,291 middle-aged civil servants and spouses of civil servants. A statistically significant negative trend with systolic blood pressure was seen for calcium intake in both males and females, even after adjustments for covariates. For sodium and potassium intake, the observed negative trends were not significant after multivariate analyses. In addition, no consistent associations were found between diastolic blood pressure and the micronutrients after multivariate analyses, except for a significant negative association with calcium intake in females. In this study population, blood pressure was a strong independent risk factor of total mortality: 15- and 25-year mortality was about twice as high for hypertensives (greater than or equal to 160 mmHg) as for normotensives (less than 160 mmHg). These findings support the conclusion in recent epidemiologic studies that higher intakes of calcium are associated with lower systolic blood pressure, and they extend the evidence to an earlier time period.

Adult↗
PubMed1982

Characteristics of individuals with multiple behavioral risk factors for coronary heart disease: the Netherlands.

To test the hypothesis that risk factors are interrelated, the simultaneous occurrence of smoking, inadequate nutrition, obesity, and physical inactivity was studied in a random sample (n = 1,951) of the Dutch adult population. Although the results did not suggest systematic clustering, the assumption of independence of these risk factors could not be maintained. Sociodemographic and health-related characteristics of the group with three or four risk factors were assessed (n = 246). Comparison with a prudent life-style group (zero risk factors, n = 387) by means by discriminant analysis indicated that the target group included proportionally more men (odds ratio: OR = 3.3), of all ages, with low education and occupation (OR = 3.5 and 1.7). The two groups did not differ in awareness of cardiovascular risk factors, preventive orientation regarding cardiovascular risk, or disease in general, and the effectiveness of health education in modifying life-style. The target group exhibited a distorted perception of the healthfulness of its own life-style and unfavorable attitudes toward modifying existing smoking, eating habits, and physical activity.

Adolescent↗
PubMed1982

Direction for nutrition education determined by target group segmentation.

Target group segmentation was carried out on the basis of data from a Dutch national survey concerning knowledge of, attitudes toward, and behavior concerning cardiovascular risk factors. Objectives were to characterize those persons with less desirable dietary practices and to seek clues for directing nutrition education to them or the primary prevention of coronary heart disease. Results of the study indicated that nutrition education should be directed primarily toward men 18 to 44 years of age, with large families, in the lower socioeconomic strata, and with food practices that are least in accord with the dietary recommendations. The education methods should include television programs as well as group counseling or face-to-face instruction directed at young families.

Adolescent↗
PubMed1982

Correlates of body mass index in 1926 Dutch men and women.

The relationship between body mass index (BMI) and demographic, socio-economic, and life-style characteristics was investigated among Dutch subjects, who participated in a nation-wide survey about knowledge, attitude and behaviour with respect to cardiovascular risk factors. A random sample of 882 men and 1044 women, aged 18 to 64 yr, was personally interviewed according to a structured questionnaire. BMI was calculated from self-reported height and body weight. To identify correlates of BMI, data were analysed by multiple regression for men and women separately. Among men a positive association of BMI was found with age, daily amount of tobacco consumption and family history of coronary heart disease (CHD). An inverse relationship was revealed for level of education, unemployment and smoking per se. Among women age, being married, widowed or divorced, and sedentary living were positively related to BMI. A negative contribution to BMI was provided by education level, familial social class and duration of leisure time physical activity.

Adolescent↗
PubMedDate not supplied

The role of hepatitis B and hepatitis C viral infections in the incidence of hepatocellular carcinoma in Sudan.

In Sudan, the incidence of hepatocellular carcinoma (HCC) is high and increasing. Hepatitis B virus (HBV) and hepatitis C virus (HCV) are important risk factors of HCC. This study aims to assess the role of HBV and HCV infections in the incidence of HCC in 2 regions of Sudan. A case-control study was conducted in 1996-98 among 150 HCC patients and 205 controls from 2 regions in Sudan. Their demographic characteristics as well as food habits and chronic conditions have been investigated. In this study, 115 cases and 199 controls were tested for hepatitis B surface antigen (HBsAg) and for HCV antibodies. Strong positive associations were found between HBV or HCV, and HCC with odds ratios (ORs) 9.8 (95% CI 5.1-18.9) and 8.3 (95% CI 2.3-29.9), respectively. After adjustment for age, by logistic regression, the ORs for HBV and HCV were 16.1 (95% CI 7.4-34.9) and 4.5 (95% CI 1.1-18.6), respectively. Further adjustment for region, education level and job type did not appreciably affect the results. Given a prevalence of HBV and HCV of 7.0% and 1.5% among controls, about 57% of all HCC cases can be attributed to these viral infections. Hepatitis infections seem to be important risk factors for HCC in Sudan.

Adult↗
PubMedDate not supplied

Determinants of p,p-dichlorodiphenyldichloroethane (DDE) concentration in adipose tissue in women from five European cities.

To identify the determinants of p,p'-dichlorodiphenyldichloroethane (p,p'-DDE) in adipose tissue in subjects who participated in a cross-sectional study, we analyzed fatty acids, antioxidants, and p,p'-DDE in aspirates of adipose tissue of 328 postmenopausal women from 5 European countries. The overall mean of p,p'-DDE concentration was 1.66 microg/g of fatty acids (95% confidence interval = 1.46, 1.88). In a multiple-regression analysis, the main predictors of log10(p,p'DDE) were center of recruitment (p < .0001), adipose arachidic acid (p = .001), and adipose retinol (p = .04). These factors explained 14.9% of the overall variability of log10(p,p'-DDE). In our subjects, adipose tissue p,p'DDE concentrations were only weakly related with biomarkers reflecting intake of fish and other foods. This result is consistent with the notion that p,p'-DDE exists in different foods and, given the widespread contamination of the food chain, is relatively evenly distributed among foods.

Adipose Tissue↗