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Biomedical subjects

R F Tas

Publications and source records attributed to R F Tas.

36 records · Page 2Linked to original sources
PubMed1990

[Multiple births in The Netherlands, 1900-1988].

There are an estimated 120,000 twins and other multiples (all still alive) in The Netherlands. The age of this population (i.e. a quarter of a million persons, 1.6% of the total population) is slightly lower compared with The Netherlands as a whole. Alterations in the structure of mother's age and birth order can only partly explain the observed changes in multiple birth frequencies. The recent increase may be due to medical treatment of women with fertility problems. In addition dizygotic twin births appear to be largely responsible for the total development in multiple births. The changes in birth patterns which relate to the demographic variables age of mother and birth order, are hardly responsible for the decline of stillbirths, perinatal and infant mortality among twins and other multiples. This improvement can be ascribed mainly to progress in medical care. In spite of this improvement, the differences compared with singles are still considerable: the stillbirth rate for twins and other multiples is 2.5 times that for singles; the perinatal mortality rate and the infant mortality rate are about four times as high. However, in the first few years of life of twins and other multiples the age-specific mortality risk declines at such a rate that as early as the third year after birth there is hardly any difference with respect to the singles.

Adolescent↗
PubMed1990

[Aliens in the Netherlands on January 1, 1990].

Data on the foreign-born population living in the Netherlands are presented and analyzed. "On January 1st 1990 there were 641 thousand aliens living in the Netherlands, i.e. 4.3% of the total population. These figures only relate to people included in Dutch municipal population registers who do not possess... Dutch nationality.... The largest category of aliens on January 1st 1990 was that of the Turks (185 thousand), followed by the 11 EC-nationalities (160 thousand) and... Moroccans (144 thousand)." (SUMMARY IN ENG)

Demography↗
PubMed1988

Twinning rate in Scandinavia, Germany and The Netherlands during years of privation.

Twinning rates were studied in Swedes, Aland Islanders, Finns, Germans, and Dutch during years of starvation when death rates were two to three times higher than average. In contrast to the situation among some animals, this study suggests that nutrition above a certain threshold is unimportant for human reproduction, including twinning. The twinning rates for these different populations display marked temporal differences, but low values in the twinning rate are not consistently associated with periods of epidemics, famine, or similar nutritional stress. After years of privation and/or separation of spouses, a rapid "catch-up effect" can often be seen in the twinning rates, as well as marriage and birth rates. Psychoendocrine factors and interparental immunological conditions that may be involved in this phenomenon are discussed.

Female↗