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.

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.

Is the ratio of apo B/apo A-I an early predictor of coronary atherosclerosis?

It is unknown which lipoprotein in childhood is the best predictor of atherosclerosis later on in life. We measured serum triglycerides, total cholesterol, its subfractions (LDL, HDL, HDL2, HDL3) and apoproteins (A-I, A-II, B) in two groups of children. They were offspring of fathers who had severe coronary atherosclerosis or no coronary sclerosis, as determined by coronary angiography. Fasting blood lipids were measured in 49 children of fathers with severe sclerosis, and in 37 children of fathers without sclerosis. Sons of fathers with severe coronary atherosclerosis had higher levels of apo B and of the ratio apo B/apo A-I than sons of fathers free of atherosclerosis. No differences in lipid levels in daughters were observed. These observations suggest that apolipoproteins play a part in early atherogenesis. They further indicate that it may be possible to detect children who have a high probability of developing severe coronary atherosclerosis later in life.

The quantification of human IgG subclasses in reference preparations.

Three laboratories took part in an investigation about the possibilities of quantitative determination of IgG subclasses. Polyclonal monospecific antisera were used in combination with different kinds of calibrators to assess the IgG subclass levels in three W.H.O. reference preparations. IgG 1 could be determined with satisfactory precision; for the other subclasses the quantification was less precise. The precision was dependent on the antisera for IgG 1, IgG 2 and IgG 4 but mainly on the calibrators for IgG 3. Mass units are to be preferred to relative units. W.H.O. reference preparation 67/97 is proposed as a reference for determination of IgG subclasses in mass units. The target values are 5.0 g/l for IgG 1, 2.6 g/l for IgG 2, 0.4 g/l for IgG 3 and 0.5 g/l for IgG 4. These values add up to a total IgG value close to earlier W.H.O. estimates.

Blood pressure and immunoglobulins.

Serum concentrations of IgG and IgM were measured in 87 hypertensive and 87 normotensive subjects, matched for age and gender, and selected from the same general population. No significant differences between these two groups were found, in contrast to some previous reports. The reasons for this discrepancy are discussed.

The absolute quantification of human IgM and IgG: standardization and normal values.

Nephelometric, turbidimetric and radial immunodiffusion methods are described, which permit valid, reproducible determination of human IgM and IgG by weight. Subgroups of IgM, 7S-IgM and subclasses of IgG did not interfere with these methods. For IgG the International Unit represented a constant weight quantity in agreement with official WHO estimations. For IgM the IU was not constant and much lower values are found. It is therefore suggested that the IU should be abolished for human IgM and IgG. Absolute values for IgM levels are presented for both sexes and for age groups in the range of 5-80 years. The figures showed significant variation with sex and age.