Biomedical subjects

A van Laar

Publications and source records attributed to A van Laar.

4 recordsLinked to original sources

PubMed1995

Multiple usage of the CD PLUS/UNIX system: performance in practice.

In August 1994, the CD PLUS/Ovid literature retrieval system based on UNIX was activated for the Faculty of Medicine and Health Sciences of Erasmus University in Rotterdam, the Netherlands. There were up to 1,200 potential users. Tests were carried out to determine the extent to which searching for literature was affected by other end users of the system. In the tests, search times and download times were measured in relation to a varying number of continuously active workstations. Results indicated a linear relationship between search times and the number of active workstations. In the "worst case" situation with sixteen active workstations, the time required for record retrieval increased by a factor of sixteen and downloading time by a factor of sixteen over the "best case" of no other active stations. However, because the worst case seldom, if ever, happens in real life, these results are considered acceptable.

CD-ROM↗

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↗

PubMed1983

Does change in blood pressure predict heart disease?

Whether a change in blood pressure is related to the occurrence of cardiovascular disease, independent of blood pressure level, was investigated using data collected in the Framingham heart study on 5209 subjects. The follow up period of 26 years was divided into a first period of 12 years in which the blood pressure change was computed for each individual and a subsequent period of 14 years in which the risk of cardiovascular disease was determined. Blood pressure change was positively related to risk of cardiovascular disease. This association remained when blood pressure level at the start of the study was taken into account but disappeared when the level attained after the first 12 years was taken into consideration. For the clinician this suggests that the decision to treat high blood pressure is best guided by the actual level of pressure and not by its long term trend in the past.

Adult↗

PubMed1982

Synergy between thinness and intensive sports activity in delaying menarche.

In a study to assess the effects of intensive physical activity and thinness on menarche records of 648 girls aged 10-14 were analysed. The girls were classified as thin or not thin on the basis of their body mass index, and whether or not they engaged in intensive sports activity was established. The presence of either thinness or intensive sports activity was associated with roughly a twofold decrease in the proportion of girls who had reached menarche; the presence of both factors was associated with roughly a fourfold decrease. These results did not appear to depend on age. Thus intensive sports activity and thinness appear to have a synergistic effect in delaying menarche.

Adolescent↗