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Biomedical subjects

L B Knudsen

Publications and source records attributed to L B Knudsen.

At least 73 records · Page 4Linked to original sources
PubMed1986

Intake of marine fat, rich in (n-3)-polyunsaturated fatty acids, may increase birthweight by prolonging gestation.

Birthweights in the Faroe Islands are among the highest in the world. Compared with Denmark, the average birthweight of liveborn singleton infants of primiparous mothers is 194 g higher, and a substantial part of this difference seems to be attributable to longer gestation. Prostaglandins play an important part in the timing of parturition in human beings. Dietary (n-3)-polyunsaturated fatty acids (PUFA) in high amounts influence endogenous prostaglandin metabolism. Owing to the large consumption of marine fat, the average intake of (n-3)-PUFA in the Faroes by far exceeds that in Denmark. The hypothesis proposed is that dietary (n-3)-PUFA in high amounts prolong gestation in human beings by interfering with uterine production of prostaglandins, possibly by inhibiting the production of dienoic prostaglandins, primarily PGF2 alpha and PGE2, which are mediators of uterine contractions and cervical ripening.

Animals↗
PubMed1986

A joint international study on the epidemiology of hypospadias.

A descriptive epidemiological study of hypospadias has been made utilizing data from seven malformation surveillance systems round the world: Denmark, Hungary, Italy, Mexico, South America, Spain, and Sweden. The joint material represents 8,122 boys with hypospadias, 7,419 of which were "isolated", that is, with no other known malformation except those obviously related to hypospadias (undescended testis, hydrocele, scrotum anomalies). The main study was based on the infants with isolated hypospadias, but an analysis of multimalformed infants with hypospadias was also made. The registered birth prevalence of isolated hypospadias varied much among the seven programs. For the years 1980-1981, the lowest recorded birth prevalence was 0.26 (Mexico) and the highest, 2.11 (Hungary). An analysis of ascertainment was made for three programs: Denmark, Hungary, and Sweden. While some uncorrect registration of infants as hypospadiac were detected, a strong underascertainment of varying degree was seen. In Hungary and Sweden, where the highest birth prevalences were recorded, there was a 30-40% underascertainment of cases later operated on; in Denmark underascertainment was still larger. When correction was made for underascertainment, the Danish and Swedish birth prevalences of isolated hypospadias were very similar. No information on ascertainment was available for the other systems, but it seems very unlikely that the low birth prevalences recorded in Mexico and South America can be solely explained by underascertainment. Therefore, it appears that true differences in the prevalence at birth of hypospadias do exist. There are no indications that the different birth prevalences depend on inclusion or exclusion of mild (distal) forms of hypospadias. There is an apparent inverse correlation between fertility in a population (estimated from mean parity in control women) and the birth prevalence of isolated hypospadias. Within each program geographical variations in birth prevalence could be seen, but the interprogram variation was larger than the intraprogram one. There is an effect of maternal age and parity on the intensity ratio of isolated hypospadias. This effect varies among programs. The variability for mothers under 20, parity 1, seems to be inversely related to the proportion of delivered women belonging to that age class. With increasing maternal age, especially within parity 1, an increased hypospadias intensity ratio is seen. Infants with isolated hypospadias show a lower birth weight and to some extent also a shorter gestational length than do controls.(ABSTRACT TRUNCATED AT 400 WORDS)

Abnormalities, Multiple↗
PubMed1986

Twinning rates by residence in Denmark 1978 to 1982.

It has been suggested in the literature that twinning rates are reduced by psychosocial stress associated with urban life. No support for this hypothesis was found in a study based upon the 5,762 twins and 280,158 singletons that were born in Denmark in the period 1978 to 1982.

Adult↗
PubMed1986

Intestinal bypass operation and pregnancy outcome.

With the aid of the national Medical Birth Registries and Discharge Registries in Denmark and Sweden it was possible to identify and study delivery outcome in 77 women who, prior to pregnancy, had undergone an intestinal bypass operation for obesity. Analysis of birth weight and pregnancy length distribution showed that infants borne by these women had an increased rate of low birth weight, short gestation, and also growth retardation. There were no distinct differences between those infants that were conceived less than 24 months or more than 24 months after operation. Only two infants had congenital malformations, none died perinatally.

Adult↗