The Netherlands twin register biobank: A resource for genetic epidemiological studies

In 2004 the Netherlands Twin Register (NTR) started a large scale biological sample collection in twin families to create a resource for genetic studies on health, lifestyle and personality. Between January 2004 and July 2008, adult participants from NTR research projects were invited into the study. During a home visit between 7:00 and 10:00 am...

Comparison of the impact of vaginal and oral administration of combined hormonal contraceptives on hepatic proteins sensitive to estrogen

Objective: We evaluated the effects of a new combined hormonal contraceptive vaginal ring (CVR) delivering the nonandrogenic progestin Nestorone® (NES) and ethinyl estradiol (EE) on several key estrogen-sensitive hepatic proteins that may be markers for the risk of arterial or venous disease events and on blood pressure (BP). Because the...

Genetics of dizygotic twinning: A feasibility study for a biobank

To locate the genes that make a substantial contribution to variation in natural dizygotic twinning in humans, large-scale studies are needed. New studies should not stop at DNA genotyping, but collect material that allow gene-expression analysis, transcriptomics, proteomics and endocrinology. In this article we describe a pilot study to examine...

Insulin, androgen, and gonadotropin concentrations, body mass index, and waist to hip ratio in the first years after menarche in girls with regular menstrual cycles, irregular menstrual cycles, or oligomenorrhea

Data on changes in hormone concentrations during the first years after menarche are scarce. We studied the relation between gynecological age (age minus age at menarche), hormone concentrations, and body measurements from the 1st to the 6th yr after menarche in 229 observations of girls with regular menstrual cycles, 157 observations of girls...

Motion sickness

The number of recently published papers on motion sickness may convey the impression that motion sickness is far from being understood. The current review focusses on a concept which tends to unify the different manifestations and theories of motion sickness. The paper highlights the relations between ergonomic principles to minimise motion...

The use of oral contraception by adolescents for contraception, menstrual cycle problems or acne

Background. Oral contraceptives are prescribed as contraception but also as therapy for menstrual cycle disturbances and acne. We studied the prevalence of oral contraceptive (OC) use and the indications to start OC use among adolescents. Methods. A cohort consisting of ninth grade secondary school girls (mean age 15.3 ± 0.6 (s.d.) years)...

Early effect of a low dose (30 μg) ethinyl estradiol-containing triphasil® on vitamin B6 status. A follow-up study on six menstrual cycles

The objectives of the study were to follow-up six artificial menstrual cycles induced by Triphasil® in order to determine: 1) the time of apparition of B6 metabolic side-effects, in the eventuality they occur, and 2) the existence or non-existence of a normalization process and if so, when it is initiated. The choice of this triphasic OC...

Delaying childbearing: Effect of age on fecundity and outcome of pregnancy

Objectives - To study the age of the start of the fall (critical age) in fecundity; the probability of a pregnancy leading to a healthy baby taking into account the age of the woman; and, combining these results, to determine the age dependent probability of getting a healthy baby. Design - Cohort study of all women who had entered a donor...

Vitamin B6 status of women suffering from premenstrual syndrome

The vitamin B6 status of women suffering from premenstrual symptoms (PMS, n = 19) and a group of matched controls (n = 19) has been investigated. The women volunteering in the study were selected on strictly defined criteria. Several biochemical parameters of the metabolism of vitamin B6 and tryptophan were studied in blood and urine samples...