Search PubMed⌕ Search

Biomedical subjects

S F Olsen

Publications and source records attributed to S F Olsen.

52 records · Page 3Linked to original sources
PubMed1992

Randomised controlled trial of effect of fish-oil supplementation on pregnancy duration.

The high birthweights and long duration of pregnancy in the Faroe Islands led us to suggest that a high intake of marine-fat-derived n-3 fatty acids might prolong pregnancy by shifting the balance of production of prostaglandins involved in parturition. We have compared the effects on pregnancy duration, birthweight, and birth length of a fish-oil supplement, a control olive-oil supplement, and no supplementation. 533 healthy Danish women in week 30 of pregnancy were randomly assigned in a ratio of 2/1/1 to fish oil (four 1 g Pikasol capsules [containing 2.7 g n-3 fatty acids] per day), olive oil (four 1 g capsules per day), or no supplement. The three groups differed in mean length of gestation (p = 0.006), which was highest in the fish-oil group and lowest in the olive-oil group; the result was similar when the analysis was restricted to women with an estimate of gestation length based on early ultrasound findings (443 women). Pregnancies in the fish-oil group were on average 4.0 (95% confidence interval 1.5-6.4) days longer than those in the olive-oil group; the difference in birthweight was 107 (1-214) g. The effect of supplementation on length of gestation was influenced by intake of fish and of fish oil: the difference between fish-oil and other groups was increased by a low fish intake at baseline. Fish-oil supplementation in the third trimester seems to prolong pregnancy without detrimental effects on the growth of the fetus or on the course of labour.

Adult↗
PubMed1991

Gestational age in relation to marine n-3 fatty acids in maternal erythrocytes: a study of women in the Faroe Islands and Denmark.

Gestation is longer in Faroese than Danish women, possibly because of the high intake of marine long-chain n-3 fatty acids that down regulates formation of prostaglandins from arachidonic acid. Polyunsaturated fatty acids were quantified in erythrocytes obtained within 2 days of delivery from randomly selected groups of 62 Faroese and 37 Danish women with an assessable gestational age. Average ratio of long-chain n-3 fatty acids to arachidonic acid [(3/6) ratio] was 0.73 (SD = 0.11) in Faroese women and 0.61 (SD = 0.12) in Danish women (p less than 0.0001), corresponding to the higher intake of marine n-3 fatty acids in the Faroes. A 20% increase in the (3/6) ratio was associated with an increase in pregnancy duration of 5.7 days in Danish women (95% confidence interval, 1.4 to 10.1 days; p = 0.02) and 0.7 days in Faroese women (95% confidence interval, -2.0 to 3.3; p = 0.6). The hypothesized exposure-effect relationship may be weaker or absent at the higher level of exposure seen in the Faroese group.

Arachidonic Acid↗
PubMed1991

Pharyngeal carriage of Neisseria meningitidis and Neisseria lactamica in households with infants within areas with high and low incidences of meningococcal disease.

In a household survey in the Faroe Islands, an isolated community with hyperendemic occurrence of meningococcal disease due to serogroup B 15, 1604 persons were examined for pharyngeal carriage of Neisseria meningitidis and N. lactamica. Two areas were chosen having experienced high (HIA), and two having experienced low incidences (LIA) of disease. Living in HIA compared with LIA was associated with higher risk of N. meningitidis B 15 carriage and lower risk of N. lactamica carriage, with odds ratios of 2.7 (95% confidence interval (CI) 1.4-5.1, P = 0.003) and 0.41 (95% CI 0.31-0.53, P less than 0.0001), respectively. In HIA the risk of N. meningitidis carriage was much lower in non-carriers than carriers of N. lactamica, with an odds ratio of 0.19 (95% CI 0.08-0.47, P = 0.0003); in LIA this association (odds ratio 0.51, P = 0.05) was much weaker. Children 0-14 years had substantially higher risk of being carriers of N. meningitidis group B 15 if the mothers were so, with an odds ratio of 11 (95% CI 4-29, P less than 0.0001).

Adolescent↗
PubMed1991

A suggestion for improving intelligibility in multivariate confounder adjustment using alcohol intake and birth weight as an example. A 'confounder score' approach in analyzing continuous data.

Adjustment for multiple confounding is usually done by applying some kind of regression model. This requires assumptions about the type of relationship between the exposure of interest and outcome. It has been suggested to use confounder scores within strata of which the relationship can be scrutinised without such assumptions. Adjusting continuous outcomes for confounding factors, like birth weight for gestational age and lung function measures for age, is sometimes done by using the ratio of the observed outcome to an outcome expected from a reference series external to the study, with a concomitant risk of introducing new confounding. In some cases, the ideas from both these approaches can, slightly modified, be successfully combined. By using an internal rather than an external reference series, i.e. a group within the data with constant exposure, expected values for outcome can be derived as the fitted values from some model, appropriate for the purpose, depicting outcome conditional on all the potential confounders that are registered and for which control is desired. The relationship between the exposure of interest and the outcome, now represented by the fractional departure for each individual from the value expected conditional on her/his confounder status, can be scrutinised without any assumptions about the form of this relationship but, contrary to the confounder score approach, on the basis of the entire data set. This method also provides a way of presenting the relationship of interest, adjusted for confounding, that is easier to understand than the traditional regression approach. The impact of alcohol intake during pregnancy on birth weight will be given as an example.

Alcohol Drinking↗
PubMed1991

Does maternal tobacco smoking modify the effect of alcohol on fetal growth?

Smoking and drinking habits were registered by a self-administered questionnaire in 36th week of gestation in 11,698 pregnant women, more than 80 percent of all such women in two Danish cities 1984-87. Alcohol consumption of 120 g/week or more was associated with a greater reduction in the average birthweight in the babies of smokers than of non-smokers (about 40 grams for the non-smokers and about 200 grams for the smokers). This is particularly striking considering that the average birthweight for smokers is lower than for non-smokers. A birthweight difference of more than 500 grams was found between babies of mothers who neither smoked nor drank and mothers who smoked and drank heavily. Our data suggest that women's smoking habits should be taken into consideration when giving pregnant women advice about drinking.

Adult↗
PubMed1990

Fish oil versus arachis oil food supplementation in relation to pregnancy duration in rats.

Throughout pregnancy, Lewis rats were fed standard rat chow supplemented with 15% (w/w) of either MaxEPA fish oil (FO) or arachis oil (AO); a third group was fed standard rat chow only (St) (n = 15, 15, and 16 rats, respectively). Compared to AO-rats, FO-rats had substantially higher levels of n-3 fatty acids and lower levels of n-6 fatty acids in maternal and fetal tissues at delivery. FO-rats had a longer average gestational age than AO-rats (p less than 0.01), primarily due to a high proportion of AO-rats with short gestations. Birthweights of FO-rats were lower than those of AO-rats (p less than 0.05), which may be related to the lower maternal weight gain during pregnancy and the lower food consumption observed in FO-rats (p less than 0.01). Litter size and occurrence of stillborn pups were not significantly different in the groups (p greater than 0.1). The findings are compatible with the hypothesis that gestational age is positively related to a high dietary intake of n-3 fatty acids.

Animals↗
PubMed1990

A possible preventive effect of low-dose fish oil on early delivery and pre-eclampsia: indications from a 50-year-old controlled trial.

A preventive effect of dietary marine n-3 fatty acids on early delivery and toxaemia has recently been hypothesized. In only one published controlled trial fish oil has been given to pregnant women, namely in that conducted during 1938-9 in London by the People's League of Health with a dietary supplement containing vitamins, minerals, and halibut liver oil. Although it was of high quality and its findings are hitherto unexplained, neglect and misinterpretation of the trial seem to occur commonly in reviews. Of the 5644 women who were enrolled the 622 withdrawals were independent of treatment. Alternate allocation to treatment was used, producing two groups that were well balanced as to age and parity. The supplement was given from about week 20. The control group did not receive any supplement. Reductions of 20.4% (95% confidence interval 9-30%, P = 0.00083) and 31.5% (95% confidence interval 11-47%, P = 0.0047) were seen in odds of delivering before 40 weeks of gestation and pre-eclampsia respectively. No significant effects were seen on perinatal mortality, average birth weight, deliveries after 40 weeks, hypertension in the absence of oedema and proteinuria, duration of labour, sepsis or breast-feeding occurrence. Later controlled trials with vitamins or minerals given in the same amounts as in this trial have largely failed to show convincing effects as seen here. A controlled trial assessing the isolated effects of fish oil in pregnancy is warranted.

Birth Weight↗
PubMed1990

Does fish consumption during pregnancy increase fetal growth? A study of the size of the newborn, placental weight and gestational age in relation to fish consumption during pregnancy.

This study investigates whether consumption of fish during pregnancy may prolong gestation or increase fetal growth. From 1984 to 1987, 11,980 pregnant Danish women filled out a questionnaire while they were in the 36th week of gestation; this was 83% of all such women living in two geographically defined areas. The women were divided into four strata dependent on having consumed a fish meal 0, 1-2, 3-4, or 5+ times during the previous month. In non-smokers, a one level increase in fish consumption was, after adjusting for 19 other variables in a multiple regression model, found to be associated with an increase of 11 g in placental weight, 0.08 cm in head circumference and 16 g in birthweight (95% confidence intervals (CI) 5 to 17 g (p = 0.0002), 0.02 to 0.14 cm (p = 0.02), and -2 to 34 g (p = 0.09), respectively); no associations with birth length or gestational age could be detected (95% Cl-0.07 to 0.11 cm (p = 0.7) and -0.82 to 0.05 days (p = 0.2), respectively, per level change in fish consumption). None of the associations seen in non-smokers were seen in smokers. We postulate that the associations seen in non-smokers could be due to marine n-3 fatty acids improving placental blood flow by increasing the ratio of prostacyclins to thromboxane. Smoking may possibly interfere with this mechanism via nicotine's inhibitory effect on platelet thromboxane production.

Animals↗
PubMed1989

Pregnancy duration and the ratio of long-chain n-3 fatty acids to arachidonic acid in erythrocytes from Faroese women.

Dietary long-chain n-3 fatty acids (FA) may prolong gestation by inhibiting formation of prostaglandins from arachidonic acid. FA were quantified in phosphatidylcholine (PC), phosphatidylethanolamine (PE), and total lipids (TL) of red cells sampled during pregnancy from 29 Faroese women. The ratio of long-chain n-3 FA to arachidonic acid (the (3/6) ratio) was used as the most relevant single measure of exposure. In 18 women with certain gestational age and with spontaneous onset of delivery, gestational age was significantly associated with the (3/6) ratio quantified in PC (correlation coefficient 0.50, P = 0.035), but not with the (3/6) ratio in PE (correlation coefficient 0.21, P = 0.40) or TL (correlation coefficient 0.29, P = 0.26). The association with the (3/6) ratio in PC could not be attributed to confounding by maternal age, weight, marital status or smoking.

Arachidonic Acids↗
PubMed1988

Dietary (n-3)-fatty acids, prostaglandins, and prolonged gestation in humans.

Prostaglandins, especially prostaglandin F2 alpha, are important regulators in the onset and maintenance of parturition in humans. Inhibition of prostaglandin formation by drugs can prolong gestation in humans. High dietary intake of long chain (n-3)-fatty acids can inhibit formation of many arachidonic acid-derived prostaglandins as well as stimulate formation of eicosapentaenoic acid-derived prostaglandins. The latter ones often have lower biological activity than the former ones. The effect of (n-3)-fatty acids on prostaglandin formation has been shown by analysis of prostaglandin metabolites in human urine. Very little is known about the tissue origin as well as the physiologicalfunctions of those prostaglandins, the metabolites of which are quantitated in urine from non-pregnant humans. In pregnant women the increased amount of prostaglandin F2 alpha-metabolites in urine, plasma and amniotic fluid probably is of uterine origin. Women in the Faroe Islands have longer gestation and are giving birth to infants with higher birth weight than women in Denmark. The Faroe Islands is a fishing community with an old cultural tradition for eating pilot whales. Fish and marine mammals are rich in long chain (n-3)-fatty acids. We have hypothesized that a high intake of long chain (n-3)-fatty acids prolongs gestation in humans by interfering with uterine prostaglandin formation, possibly by inhibiting formation of prostaglandin F2 alpha and prostaglandin E2. Preliminary results of an epidemiological observational study have shown a positive correlation between (n-3)-fatty acids in maternal erythrocytes and length of gestation. These results are in accordance with our hypothesis, but a causal relationship remains to be shown.

Animals↗
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↗
PubMed1985

High liveborn birth weights in the Faroes: a comparison between birth weights in the Faroes and in Denmark.

The average birth weight of 10 132 liveborn infants delivered in the Faroes during the period 1969-81 was 3610 grams, which is the highest average weight reported by 33 countries from which we were able to obtain information. Comparison of live births only between the Faroes and Denmark shows a displacement between their birth weight curves of 225 grams. A less active elective delivery in the Faroes could not explain this considerable difference. When standardisation is made with respect to discrepancies in maternal age and marital status in the two populations, the difference between their average birth weights is increased by 5% and 9% respectively. A matching for maternal parity yields a difference between the averages which is 23% below the one between the total populations. Other factors must be responsible. Both environmental and genetic factors plus the possibility of the Faroes being closer to having an optimal birth weight than other countries are discussed.

Adolescent↗
PubMed1983

Calmodulin binding to secretory granules isolated from bovine neurohypophyses.

Secretory granules, isolated from bovine neurohypophyses on isoosmolar Percoll-sucrose-EGTA gradients had a calmodulin content of 0.09 +/- 0.01 micrograms/mg protein (SE, n = 6). The distribution of calmodulin on the gradient showed that it did not copurify with the granules. Specific binding sites for calmodulin with a high affinity (Kd = 2.43 +/- 0.27 X 10(-9) M (SE, n = 5] and a maximum binding capacity of 1.3 +/- 0.4 pmol/mg protein (SE, n = 5) could be demonstrated when such secretory granules were incubated with 125I-calmodulin.

Animals↗
PubMed1982

The differentiation hypothesis: distinguishing between perceiving and memorizing.

The differentiation hypothesis states that perceiving and memorizing are functionally undifferentiated for young children (preschoolers). With age, additional strategies are implemented under intentional recall conditions, thus providing greater recall than under incidental conditions. Appel and colleagues presented initial evidence in 1972 that appeared to support the predicted Age X Recall Instruction (incidental, intentional) interaction of the differentiation hypothesis. Subsequent research in children's memory, however, has failed to replicate the critical features of the Appel et al. data. A closer look at Appel et al.'s procedures revealed a methodological flaw present in both their Experiments 1 and 2--the variable of instructional condition was manipulated within subjects. In addition, an inspection of their reported Age X Instruction interaction revealed a larger quadratic than linear component. The difference between incidental and intentional recall first increased and then decreased with age. Correcting for these errors of method and analysis, the present experiment found no support for the differentiation hypothesis. Recall did increase with age, but the increase was not differential with respect to incidental or intentional recall instructions.

Attention↗