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Biomedical subjects

R T Lie

Publications and source records attributed to R T Lie.

At least 37 records · Page 2Linked to original sources
PubMed2000

Seasonal variation in risk of anemia among pregnant Nepali women.

OBJECTIVE: We aimed to investigate whether there is any seasonal variation in risk of anemia among pregnant Nepali women. METHODS: We studied the hematocrit values in pregnant women (n=5495) attending Patan Hospital, Kathmandu for the first antenatal visit in the 2-year period from January 1994 until December 1995. In a sub-sample of subjects (n=2706), additional information was obtained through interviews and clinical examinations. Logistic regression models were used to analyze data. RESULTS: Mean hematocrit values recorded in the monsoon period were significantly lower than hematocrit values recorded in the winter. The prevalence of moderate (hematocrit 25-33%) and severe (hematocrit<25%) anemia was highest in September. CONCLUSIONS: We found a clear seasonal variation in risk of anemia, which was associated with rainfall and temperature. The monsoon seems to be a period when interventions may give the most beneficial effects.

Adolescent↗
PubMed2000

Anaemia in pregnancy: possible causes and risk factors in Nepali women.

OBJECTIVE: The aim of this study was to investigate the importance of nutritional deficiencies and infections in the development of anaemia in pregnant Nepali women. DESIGN: Case-control study. SETTING: Patan Hospital, Kathmandu, Nepal. SUBJECTS: A sub-sample (n=479) of all pregnant women (n=2856) coming for their first antenatal visit in a 12 month period, 1994-1995. Women who had already received any micronutrient supplementation (n=82), and those whose serum samples showed macroscopic haemolysis (n=7) were excluded. The remaining women (n=390) were included in the statistical analysis. They were divided into three groups; a non-anaemic control group, haematocrit (Hct)>33% (n=82), and two case-groups: moderately anaemic, Hct 25-33% (n=254), and severely anaemic, Hct<25% (n=54). RESULTS: We found high prevalences of nutritional deficiencies and intestinal infections, both among cases and controls. The prevalence of low s-ferritin was high, especially among the severely anaemic women (55.6%). In a multiple logistic regression model, the presence of low s-vitamin A, elevated s-C-reactive protein or hookworm infection was associated with a significantly increased risk of severe anaemia. The adjusted odds ratios (95% CI) were 8.38 (1.99, 35.30), 4.91 (1.22, 19.67) and 5.43 (1.20, 24.61), respectively. CONCLUSIONS: In addition to the present routine iron and folate supplementation to pregnant Nepali women, vitamin A supplementation needs to be considered. Prevention and treatment of infections should, together with dietary advice, be emphasized more strongly in the antenatal care. SPONSORSHIP: The Norwegian Research Council and the Norwegian Universities Committee for Development, Research and Education. European Journal of Clinical Nutrition (2000) 54, 3-8

Adolescent↗
PubMed2000

Estimates of maternal mortality by the sisterhood method in rural nothern Tanzania: a household sample and an antenatal clinic sample.

OBJECTIVE: To estimate maternal mortality in two samples of a population in northern Tanzania. SETTING: Rural communities and antenatal clinics, Mbulu and Hanang districts, Arusha region, Tanzania. POPULATION: From a household survey 2,043 men and women aged 15-60, and from an antenatal clinic survey 4,172 women aged 15-59. METHOD: The indirect sisterhood method. MAIN OUTCOME MEASURES: The risk of maternal deaths per 100,000 live births (maternal mortality ratio), and the lifetime risk of a maternal death. RESULTS: The risk of a maternal death per 100,000 live births was 362 (95% CI 269-456) and 444 (95% CI 371-517) for the household and antenatal clinic surveys, respectively. The lifetime risk of maternal death was 1 in 38 and 1 in 31, respectively, for the two surveys. A significantly lower risk of maternal death was observed for the respondents attending antenatal clinics closer to the hospital than for those attending clinics further away: 325 (95% CI 237-413) compared with 561 (95% CI 446-677) per 100,000 live births. Lifetime risk of maternal death was 1 in 42 and 1 in 25, respectively. CONCLUSIONS: The risk of maternal death per 100,000 live births in this area were comparatively high, but in our survey substantially lower than in previous surveys in Tanzania. Increasing distance from the antenatal clinics to the hospital was associated with higher maternal mortality. There was no significant difference between results based on household and antenatal clinic data, suggesting that accessible health facility data using the sisterhood method may provide a basis for local assessment of maternal mortality in developing countries.

Adolescent↗
PubMed2000

The prevalence of anemia in pregnant Nepali women--a study in Kathmandu.

BACKGROUND: Anemia in pregnancy is associated with maternal and perinatal morbidity and mortality. The World Health Organization has suggested that where up-to-date information is not available, prevalence studies should be undertaken. METHODS: The distribution of hematocrit in 2280 pregnant women attending Patan Hospital, Kathmandu, for their first antenatal visit in a twelve month period, 1994-95, was studied. Anemia was defined as a hematocrit value < or =34% in the first and third trimesters, or < or =33% in the second trimester. Severe anemia was defined as a hematocrit value < or =24%. The prevalence of anemia and severe anemia, and associations with socio-demographic (age, ethnic group, living area, maternal and paternal education and occupation) and biological (height, body mass index, parity, gestation) variables were investigated. RESULTS: The hematocrit values ranged from 11-49% with a mean value of 32.6% (s.d. 3.9). The prevalences of anemia and severe anemia were 62.2% and 3.6%, respectively. High prevalence of anemia was observed among teenagers, farmers, women of short height, the ethnic groups Lama/Sherpa/Tamang, and women married to industrial workers or illiterate men. Also, the risk of anemia increased with gestation. Work within the service professions, higher education and high body mass index, were associated with a lower risk of anemia. CONCLUSIONS: A high prevalence of anemia among pregnant women in Kathmandu was observed. The hematocrit values were related to socio-demographic and biological factors. In order to plan focused and effective intervention, studies on the etiology of anemia among pregnant women in rural and urban areas of Nepal need to be carried out.

Adolescent↗
PubMed2000

Assessing quality of obstetric care for low-risk deliveries; methodological problems in the use of population based mortality data.

BACKGROUND: Studies evaluating safety of different birth settings for low-risk deliveries are often difficult to interpret because of great methodological problems. OBJECTIVE: To assess potential bias in comparisons of mortality between maternity institutions with different size and level of care, particularly when using various definitions of low-risk delivery and when studying stillbirth rates. DESIGN: Population-based study. POPULATION: The population of 1.74 million births in Norway from 1967 to 1996 recorded in The Medical Birth Registry of Norway. METHODS: First we explored the problems of properly identifying low-risk deliveries from population-based data and calculated adjusted perinatal mortality rates in sub-populations by excluding different risk factors. Then we measured the difference in apparent low-risk deliveries between institutions of different size and level of care. Finally we explored bias by using stillbirths and discuss the loss of statistical power by studying only livebirths. RESULTS: The occurrence of a whole spectrum of risk factors differed between small and large institutions, even after adjustment for birthweight. Although the majority of births were from low-risk deliveries, only 1/10th of all perinatal deaths occurred in this group after admission to a maternity unit. There was a systematic difference in the reporting of time of death for stillbirths between types of institutions; the rate of stillbirths occurring during delivery was higher among small institutions, while large institutions were more often uncertain in classifying time of death for stillbirths. CONCLUSIONS: Adjustments for a large number of different risk factors, large sample-sizes and caution in including stillbirth as outcome measure are needed when comparisons of safety between different sizes of delivery units are made for low-risk pregnancies.

Adult↗
PubMed2000

The diagnosis of urinary tract infections among pregnant women in rural Tanzania; prevalences and correspondence between different diagnostic methods.

BACKGROUND: To assess the prevalence of dysuria, dipsticks positive on nitrite and leukocyte esterase and positive Uricult dip slides among pregnant women in rural Tanzania. METHODS: 3,715 pregnant women were examined for dysuria and had their urine tested with nitrite and leukocyte esterase dipsticks and Uricult dipslides, at their first antenatal visit in 1995-96. RESULTS: The prevalences of positive symptoms and tests were as follows: dysuria 32%, nitrite 40.3%, leukocyte esterase 65.6%, and Uricult dip slides 16.4%. A general log-linear model where all four variables were analyzed simultaneously showed poor correspondence between the diagnostic methods. Odds ratio with 95% confidence intervals were as follows: dysuria vs. nitrite [1.6 (1.4 1.8)]. dysuria vs. leukocyte esterase [1.2 (1.0-1.4)], nitrite vs. leukocyte esterase [4.2 (3.6-4.9)], and leukocyte esterase vs. Uricult [1.4 (1.1-1.7)]. Dysuria and nitrite were not associated with Uricult dipslide. CONCLUSION: A high prevalence of positive tests, but a poor correspondence between the methods was found, emphasizing the need for more attention to the problem of urinary tract infections among pregnant women in developing countries, and the need for better screening tests for urinary tract infections in these countries.

Adolescent↗
PubMed1999

A population-based study of survival and childbearing among female subjects with birth defects and the risk of recurrence in their children.

BACKGROUND AND METHODS: Persons with birth defects are at high risk for death during the perinatal period and infancy. Less is known about the later survival or reproduction of such persons. We studied a cohort that comprised 8192 women and adolescent girls with registered birth defects and 451,241 women and adolescent girls with no birth defects, all of whom were born in Norway from 1967 through 1982. The rate of survival was determined through 1992, and the rate of childbearing was determined through October 1997. We also estimated the risk of birth defects in the children of these subjects. RESULTS: Among the subjects with birth defects, 80 percent survived to 15 years of age, as compared with 98 percent of those with no birth defects. Among the surviving subjects, 53 percent of those with birth defects gave birth to at least one infant by the age of 30 years, as compared with 67 percent of those with no birth defects. The subjects with birth defects were one third less likely to give birth by the age of 30 than those with no birth defects. The children of the subjects with birth defects had a significantly higher risk of birth defects than the children of those with no birth defects (relative risk, 1.6; 95 percent confidence interval, 1.3 to 2.1). This increased risk was confined entirely to the specific defect carried by the mother, with the relative risk of recurrence varying from 5.5 to 82 according to the defect. In contrast, there was no increase in the risk of having an infant with a different type of defect. CONCLUSIONS: Women and girls with birth defects have decreased survival as compared with those with no birth defects, especially in the first years of life, and are less likely to have children. In addition, they have an increased risk of having children with the same defect.

Adolescent↗
PubMed1999

Consanguinity and recurrence risk of birth defects: a population-based study.

Recurrence risks give insight into the causes of birth defects and are useful in genetic counseling. There are few population-based studies of recurrence of birth defects for subsequent sibs with consanguineous parents. The aim of this study was to estimate and compare the recurrence risk of birth defects for offspring of first cousins and nonconsanguineous parents. The study population consisted of all single births with a previous sib born in Norway between 1967 and 1995. Altogether 660,398 children had nonconsanguineous parents, and 3,583 had parents who were first cousins. For nonconsanguineous parents the risk of a birth defect for the subsequent sib was 15 per 1,000 births (95% confidence interval: 14.5-15.1) if the previous child did not have a birth defect and 33 (95% confidence interval: 30-37) if the previous child had a birth defect. For parents who were first cousins the risk of a birth defect for the subsequent sib was 36 per 1,000 (95% confidence interval: 30-42) if the previous child did not have a birth defect and 68 (95% confidence interval: 33-122) if the previous child had a birth defect. The risk of recurrence of birth defects is higher for subsequent sibs with first-cousin parents than for those with nonconsanguineous parents. This difference indicates the degree to which the increased homozygosity among offspring of consanguineous parents influences the risk of recurrence of birth defects.

Age Factors↗
PubMed1999

Causes of death in patients with peptic ulcer perforation: a long-term follow-up study.

BACKGROUND: Survival is lower in ulcer perforation patients than in the general population. This study assesses the causes of death in patients treated for peptic ulcer perforation. METHODS: Cause-specific mortality in a population-based cohort of 817 patients treated for ulcer perforation in western Norway during the period 1962-1990 was compared with cause-specific population death rates. Analyses were based on observed and expected mortality curves for major causes of death and on standardized mortality rates (SMRs). Cox regression models were used to analyse possible differences on the basis of sex, birth cohort, surgical procedure, and ulcer location. RESULTS: Ulcer perforation patients experienced increased mortality from neoplasms (SMR = 1.8; 95% confidence interval (CI) = 1.4-2.1), lung cancer (SMR = 3.6; 95% CI = 2.3-4.9), circulatory diseases (SMR = 1.3; 95% CI = 1.1-1.6), ischaemic heart disease (SMR = 1.3; 95% CI = 1.03-1.6), and respiratory diseases (SMR = 1.9; 95% CI = 1.3-2.6). Postoperative deaths accounted for 38% of all excess deaths. Death from recurrent peptic ulcer was increased also in subjects who survived the 1st year after the perforation (SMR = 5.8; 95% CI = 1.2-10.4) but accounted for only a few deaths. The increase in mortality from lung cancer was higher in subjects born after 1910 than in patients of older generations. Excess mortality from lung cancer and from circulatory diseases was higher in male than in female patients. CONCLUSIONS: Increased mortality in ulcer perforation patients could mainly be attributed to smoking-related diseases. This is indirect evidence that smoking may be an important aetiologic factor for ulcer perforation.

Cardiovascular Diseases↗
PubMed1999

Relation between size of delivery unit and neonatal death in low risk deliveries: population based study.

AIM: To examine risk of neonatal death after low risk pregnancies in relation to size of delivery units. METHODS: A population based study of live born singleton infants in Norway with birthweights of at least 2500 g was carried out. Antenatal risk factors were adjusted for. RESULTS: From 1972 to 1995, 1.25 million births fulfilled the criteria. The neonatal death rate was lowest for maternity units with 2001-3000 annual births and steadily increased with decreasing size of the maternity unit to around twice that for units with less than 100 births a year (odds ratio 2.1; 95 % confidence interval 1.6 to 2.8). Institutions with more than 3000 deliveries a year also had a higher rate (odds ratio 1.7; 95% CI 1.4 to 2.0), but analyses suggest that this rate is overestimated. CONCLUSION: Around 2000 to 3000 annual births are needed to reduce the risk of neonatal deaths after low risk deliveries.

Birth Rate↗
PubMed1999

Consanguinity and recurrence risk of stillbirth and infant death.

OBJECTIVES: The aim of this study was to estimate the recurrence risk for stillbirth and infant death and compare results for offspring of first-cousin parents with results for offspring of unrelated parents. METHODS: The study population consisted of all single births with a previous sibling born in Norway between 1967 and 1994. Altogether, 629,888 births were to unrelated parents, and 3466 births were to parents who were first cousins. The risk of stillbirth and infant death was estimated for subsequent siblings contingent on parental consanguinity and survival of the previous sibling. RESULTS: For unrelated parents, the risk of early death (stillbirth plus infant death) for the subsequent sibling was 17 of 1000 if the previous child survived and 67 of 1000 if the previous child died before 1 year of age. For parents who were first cousins, the risk of early death for the subsequent sibling was 29 of 1000 if the previous child survived and 116 of 1000 if the previous child died. CONCLUSIONS: The risk of recurrence of stillbirth and infant death is higher for offspring of first-cousin parents compared with offspring of unrelated parents.

Adult↗
PubMed1998

Distinguishing the effects of maternal and offspring genes through studies of "case-parent triads".

A gene variant that increases disease risk will be overrepresented among diseased persons, even compared with their own biologic parents. This insight has led to tests based solely on the asymmetric distribution of a variant allele among cases and their parents (e.g., the transmission/disequilibrium test). Existing methods focus on effects of alleles that operate through the offspring genotype. Alleles can also operate through the mother's genotype, particularly for conditions such as birth defects that have their origins in fetal life. An allele working through the mother would have higher frequency in case-mothers than in case-fathers. The authors develop a log-linear method for estimating relative risks for alleles in the context of case-parent triads. This method is able to detect the effects of genes working through the offspring, the mother, or both. The authors assume Mendelian inheritance, but Hardy-Weinberg equilibrium is unnecessary. Their approach uses standard software, and simulations demonstrate satisfactory power and confidence interval coverage. This method is valid with a self-selected or hospital-based series of cases and helps to protect against misleading inference that can result when cases and controls are randomly sampled from a population not in Hardy-Weinberg equilibrium.

5,10-Methylenetetrahydrofolate Reductase (FADH2)↗
PubMed1998

Influence of consanguinity and maternal education on risk of stillbirth and infant death in Norway, 1967-1993.

To analyze the influence of consanguinity and maternal education on stillbirth and infant death for children born in Norway between 1967 and 1993, the authors studied 7,274 children of ethnic Pakistani origin and 1,431,055 children of Norwegian ethnic origin. Of these children, 31.0% of the Pakistani children and 0.1% of the Norwegian children had parents who were first cousins. Consanguinity increased the relative risk of stillbirth (odds ratio (OR) = 1.3, 95% confidence interval (CI) 1.0-1.6) and infant death (OR = 2.4, 95% CI 2.0-3.0), after adjustment for maternal education, maternal age, parity, and year of birth. In 1985-1993, 29% (95% CI 13-45) of stillbirths and infant deaths among the Pakistani group were attributable to consanguinity. In the Norwegian group, 17% (95% CI 13-21) of the deaths were attributable to factors associated with low maternal education, while in the Pakistani group, the corresponding estimate was nonsignificant. The risks of stillbirth and infant death were similar for children with non-consanguineous parents in both populations. This is an important observation considering the differences in socioeconomic status between the two groups. The authors conclude that consanguinity influenced stillbirth and infant death independent of maternal education, and that a large proportion of deaths could be attributed to consanguinity in the Pakistani group due to high frequencies of consanguinity.

Consanguinity↗
PubMed1998

Expected survival compared with survival of peptic ulcer patients.

In analyses of patient survival it is often desirable to compare observed survival curves with expected survival curves based on information obtained from the general population. However, current methods of calculating expected survival curves are difficult to interpret and are often poorly documented. We discuss an alternative formulation of the so-called direct method which we recommend for general use. By simulation, we show that the expected survival curve obtained from this method represents the expectation of a Kaplan-Meier curve for a set of random population controls. Thus, the term expected survival does not refer to the expectation of patient survival, but rather to the expected survival curve for a random set of controls. The alternative methods are discussed, and we illustrate the methods in an analysis of long time survival of a population-based sample of peptic ulcer patients.

Age Factors↗
PubMed1998

Fetal and maternal contributions to risk of pre-eclampsia: population based study.

OBJECTIVE: To use familial patterns of recurrence of pre-eclampsia to investigate whether paternal genes expressed in the fetus contribute to the mother's risk of pre-eclampsia and whether mother's susceptibility to pre-eclampsia is related to maternal inheritance by mitochondrial DNA. DESIGN: Linked data on pregnancies of different women who had children with the same father, and subsequently linked data on pregnancies of half sisters who either had same mother and different fathers or had same father and different mothers. SETTING: Population based data from the Medical Birth Registry of Norway covering all births since 1967 (about 1.7 million) and the Norwegian Central Population Register. MAIN OUTCOME MEASURES: Relative risk of pre-eclampsia after a previous pre-eclamptic pregnancy in the family. Relative risks approximated by odds ratios. RESULTS: If a woman becomes pregnant by a man who has already fathered a pre-eclamptic pregnancy in a different woman her risk of developing pre-eclampsia is 1.8 (95% confidence interval 1.2 to 2.6). If the woman has a half sister who had pre-eclampsia and with whom she shares the same mother but different fathers the risk of pre-eclampsia is 1.6 (0.9 to 2.6). If the two sisters have the same father but different mothers the risk is 1.8 (1.01 to 2.9). CONCLUSIONS: Both the mother and the fetus contribute to the risk of pre-eclampsia, the contribution of the fetus being affected by paternal genes. Mitochondrial genes, which are transmitted by mothers, do not seem to contribute to the risk.

Fathers↗
PubMed1998

A log-linear approach to case-parent-triad data: assessing effects of disease genes that act either directly or through maternal effects and that may be subject to parental imprinting.

We describe a log-linear method for analysis of case-parent-triad data, based on maximum likelihood with stratification on parental mating type. The method leads to estimates of association parameters, such as relative risks, for a single allele, and also to likelihood ratio chi2 tests (LRTs) of linkage disequilibrium. Hardy-Weinberg equilibrium need not be assumed. Our simulations suggest that the LRT has power similar to that of the chi2 "score" test proposed by Schaid and Sommer and that both can outperform the transmission/disequilibrium test (TDT), although the TDT can perform better under an additive model of inheritance. Because a restricted version of the LRT is asymptotically equivalent to the TDT, the proposed test can be regarded as a generalization of the TDT. The method that we describe generalizes easily to accommodate maternal effects on risk and, in fact, produces powerful and orthogonal tests of the contribution of fetal versus maternal genetic factors. We further generalize the model to allow for effects of parental imprinting. Imprinting effects can be fitted by a simple, iterative procedure that relies on the expectation-maximization algorithm and that uses standard statistical software for the maximization steps. Simulations reveal that LRT tests for detection of imprinting have very good operating characteristics. When a single allele is under study, the proposed method can yield powerful tests for detection of linkage disequilibrium and is applicable to a broader array of causal scenarios than is the TDT.

Computer Simulation↗
PubMed1997

Birth defects and parental consanguinity in Norway.

The study compares frequencies of birth defects between immigrant groups and the rest of the Norwegian population in Norway and estimates the influence of consanguinity and socioeconomic factors on these frequencies. The authors studied all 1.56 million births in Norway from 1967 to 1993. Of these, 7,494 children had two Pakistani parents, 84,688 had one Norwegian and one immigrant parent, and 25,891 had two immigrant parents from countries other than Pakistan. The risk of birth defects relative to the Norwegian group was 0.98 (95% confidence interval 0.92-1.03) in the group with one foreign and one Norwegian parent, 1.39 (95% confidence interval 1.22-1.60) in the group with two Pakistani parents, and 1.04 (95% confidence interval 0.95-1.14) in the group with two parents from other foreign countries; 0.1% of the Norwegian and 30.1% of the Pakistani children had parents who were first cousins. There was no difference in risk between children of nonconsanguineous Pakistani parents and the other groups. The relative risk of birth defects among children whose parents were first cousins was about 2 in all groups. Among the Pakistani, 28% of all birth defects could be attributed to consanguinity. Low paternal educational level was associated with a slightly increased risk in the Norwegian group, while independent effects of parental educational levels were not found in any other groups.

Confidence Intervals↗