Biomedical subjects

P Magnus

Publications and source records attributed to P Magnus.

At least 127 records · Page 7Linked to original sources

PubMed1994

[The extent of HIV testing in the Norwegian population seen in relation to sex behavior].

To estimate the incidence of clinical HIV-testing and the association between testing and sexual habits, data from a 1992 population-based, anonymous survey of sexual behaviour were analysed. The sample size was 10,000 subjects between 18 and 60 years of age and the response rate was 48%. 15% of the males and 13% of the females reported having been HIV-tested at least once during the period 1985-92, and 1% of the sample four times or more. The incidence of testing has increased. However, a decrease in first time testing was observed after 1990. The best predictors of HIV-testing are the partner's test behaviour and the number of sexual partners during a lifetime.

AIDS Serodiagnosis↗

PubMed1994

[Risk of AIDS in the Oslo HIV-cohort study. A comparison between homosexual men, intravenous addicts and heterosexual persons].

In order to study differences in risk of the development of AIDS in different groups of HIV infected subjects, 151 homosexual men, 110 intravenous drug users (IVDUs) and 36 heterosexually infected persons without major signs of HIV infection at entry to the study were enrolled in a cohort study. The mean follow-up time was 35 months. At the end of follow-up 40 subjects (13%) were diagnosed as having AIDS. This represented 20% (31/151) of the homosexual men, 7% (8/110) of the IVDUs and 3% (1/36) of the heterosexual subjects. The probability of being AIDS-free 36 months after entering the study was 0.88 (0.84-0.92, 95% CI) for the total study population, 0.83 (0.77-0.90) for the homosexual men, 0.92 (0.86-0.99) for IVDUs and 0.93 (0.91-1.0) for heterosexual subjects (p < 0.05, log rank test). In a Cox regression analysis, adjusting for CD4+ cell count at study entry, the relative risk of AIDS progression was 2.4 (1.1-5.2) for homosexual men and 0.3 (0.04-2.4) for heterosexual subjects, compared with IVDUs. The results demonstrate a higher risk of AIDS for homosexual men during the follow-up period.

Acquired Immunodeficiency Syndrome↗

PubMed1994

No differential heritability of intelligence test scores across ability levels in Norway.

The possibility of differential heritability of intelligence test scores across levels of ability has been raised in several recent reports. In the present paper intelligence test data from 862 monozygotic and 1325 dizygotic male twin pairs tested at about 19 years of age were analyzed in search for changes in heritability and shared environmentality as a function of ability level. The analyses were performed by means of multiple regression models (e.g., Cherny et al., 1992). No evidence of differential heritability across different ability levels was detected.

Adult↗

PubMed1994

The core group revisited: the effect of partner mixing and migration on the spread of gonorrhea, Chlamydia, and HIV.

A set of differential equations are used to model the spread of sexually transmitted diseases (STDs) in a one-sex population that includes a core group of highly sexually active subjects. The effects of partner mixing between groups and migration to and from the core on the equilibrium number of infected are shown for gonorrhea, chlamydia, and HIV. The STDs are described by the transmission probability per sexual contact and the duration of infectiousness. Partner change and intercourse frequencies are estimated from sexual survey data on heterosexual behavior. The core group is small (3% of the total population) with a partner change frequency 15 times and an intercourse frequency 2 times that of the remaining population. The degree of partner mixing and migration between the two groups can be varied. The number of sexual contacts in the three types of partnerships (core-core, "mixed," remaining population-remaining population) is also modeled. The mixed partnerships are assumed to be casual and to have a low frequency of intercourse. The model is fairly simple, and the emphasis is on qualitative rather that predictive results. The effects of partner mixing are found to be strikingly different for gonorrhea, chlamydia, and HIV. With increasing partner mixing between groups, gonorrhea shows a small increase and then a decrease in the total number of infected, whereas chlamydial infection shows a strong increase. For HIV infection the effect depends on the transmission probability; when it is 0.001 per sexual contact, the number of infected with HIV is almost unaffected by the partner mixing, and when the transmission probability is 0.002 per sexual contact, there is a strong increase in the number of HIV infected with increasing partner mixing. The effects of migration are also different for each disease. With increasing migration between groups, gonorrhea is almost unaffected in the total number of infected, whereas chlamydial infection shows a strong increase. For HIV the effect again depends on the transmission probability; when it is 0.001 per sexual contact, the number of infected with HIV shows a strong decrease, and when the transmission probability is 0.002 per sexual contact the number of HIV infected reaches its maximum for medium strong migration. A sensitivity analysis shows that for all three diseases the basic reproductive ratios (R0) and the total number of infected are sensitive to duration of infectiousness. In addition, for gonorrhea and chlamydia, RO is sensitive to the partner change rates in the core, whereas for HIV, RO is sensitive to the frequency of intercourse in the core.(ABSTRACT TRUNCATED AT 400 WORDS)

Chlamydia Infections↗

PubMed1994

Asymptomatic carriage of Neisseria meningitidis in a randomly sampled population.

To estimate the extent of meningococcal carriage in the Norwegian population and to investigate the relationship of several characteristics of the population to the carrier state, 1,500 individuals living in rural and small-town areas near Oslo were selected at random from the Norwegian National Population Registry. These persons were asked to complete a questionnaire and to volunteer for a bacteriological tonsillopharyngeal swab sampling. Sixty-three percent of the selected persons participated in the survey. Ninety-one (9.6%) of the volunteers harbored Neisseria meningitidis. The isolates were serogrouped, serotyped, tested for antibiotic resistance, and analyzed by multilocus enzyme electrophoresis. Eight (8.8%) of the 91 isolates represented clones of the two clone complexes that have been responsible for most of the systemic meningococal disease in Norway in the 1980s. Age between 15 and 24, male sex, and active and passive smoking were found to be independently associated with meningococcal carriage in logistic regression analyses. Working outside the home and having an occupation in transportation or industry also increased the risk for meningococcal carriage in individuals older than 17, when corrections for gender and smoking were made. Assuming that our sample is representative of the Norwegian population, we estimated that about 40,000 individuals in Norway are asymptomatic carriers of isolates with epidemic potential. Thus, carriage eradication among close contacts of persons with systemic disease is unlikely to have a significant impact on the overall epidemiological situation.

Adolescent↗

PubMed1994

Slow progression to AIDS in intravenous drug users infected with HIV in Norway.

STUDY OBJECTIVE: To study the rate of progression to AIDS and to death, and the causes of death among intravenous drug users in Norway. DESIGN: This was a prospective study. The study population was followed from diagnosis of HIV seropositivity until death or the end of the study period. The mean follow up was 56 months (range 1-73 months). SETTING: Subjects were recruited from a public HIV test clinic and followed by linkage to the National AIDS Registry and the National Cause of Death Registry. PARTICIPANTS: A total of 131 HIV positive intravenous drug users were included. The study population represented 75% of all intravenous drug users who had been diagnosed as HIV positive in Norway before 1987. None were lost to follow up. MAIN RESULTS: Four years after study entry, 3% (95% confidence interval, 0, 6%) had developed AIDS, while 15% (95% CI, 9, 21%) had died. Of the 25 subjects who died during the follow up period, 21 died from unnatural causes. Drug overdose accounted for 17 of these deaths. AIDS was the cause of death of three subjects only. Age more than 30 years at entry to the study was associated with short survival. CONCLUSIONS: These results suggest that the progression rate to AIDS in intravenous drug users is slow.

Acquired Immunodeficiency Syndrome↗

PubMed1994

A comparison of the progression rate to acquired immunodeficiency syndrome between intravenous drug users and homosexual men.

In order to study differences in progression to Acquired Immunodeficiency Syndrome (AIDS) between risk groups, 205 homosexual men and 185 intravenous drug users (IVDUs) were followed from diagnosed seropositivity for Human Immunodeficiency Virus Type-1 (HIV) for a mean period of 46 months (range 1-88 months). Seven (4%) IVDUs and 55 homosexual men (27%) were diagnosed with AIDS during the follow-up period. The probability of being AIDS-free four years after diagnosed HIV positivity was 0.96 for IVDUs (SE 0.02) and 0.73 (SE 0.04) for homosexual men (p < 0.001, log rank test). When controlling for age and gender, the relative risk of AIDS progression for homosexual men was 9.1 (3.5-24.1, 95% confidence interval) as compared with IVDUs. Even when 24 months of follow-up time without progression were added for all homosexual men, assuming that the epidemic started two years earlier in this group, the relative risk of progression was 5.4 (2.1-14.4, 95% confidence interval) for homosexual men.

Acquired Immunodeficiency Syndrome↗

PubMed1994

Aluminium potroom asthma: the Norwegian experience.

Work-related asthma in aluminium potroom workers, is reviewed and discussed, mainly on the basis of own investigations. The occurrence of work-related asthma has been shown to be associated with the duration of potroom employment, although the prevalence of asthmatic symptoms is not significantly different from that of the general population. Typical manifestations of occupational asthma are described in potroom workers, and a close relationship between the levels of fluoride exposure and work-related asthmatic symptoms has been observed. The existence of occupational asthma in aluminium potroom workers has been confirmed by characteristic patterns of repeated peak flow measurements, supported by changes in methacholine responsiveness in workers with suspected work-related asthma. However, no immunological test is available to establish the diagnosis. Methacholine challenge appears to be inappropriate for screening aluminium potroom workers in order to detect work-related asthma. Current smoking, but not self-reported allergy, is a risk factor for potroom asthma. A family history of asthma and previous occupational exposure may have some effect on the risk of developing symptoms. The prognosis of potroom asthma seems to depend on early replacement to unexposed work. The pathogenetic mechanisms are unknown, although some studies indirectly imply a hypersensitivity reaction. Future studies involving specific bronchial challenge appear to be necessary to find the causal agent(s) of aluminium potroom asthma.

Aluminum↗

PubMed1994

Lung function by tidal breathing in awake healthy newborn infants.

The increasing availability of appliances for measuring lung function in infants may allow clinical and epidemiological applications. The aim of the present study was to establish reference values for tidal breathing lung function in awake newborn infants and to investigate potential sources of variability. Tidal flow-volume loops were measured in 803 awake, healthy infants (427 males and 376 females) and passive respiratory mechanics (single-breath occlusion technique) in 664. Mean postnatal age was 2.7 +/- 0.9 (sd) days, gestational age 39.8 +/- 1.4 weeks and birthweight 3.59 +/- 0.49 kg. Tidal expiratory volume (Vt), peak tidal expiratory flow (PEF), and mid-expiratory flow increased significantly with increasing birthweight. Flow ratios: ratio of time to PEF to total expiratory time (Tpef/Te), ratio of volume to PEF to total expiratory volume (Vpef/Ve); and ratio of tidal flow at 25% remaining expiration to PEF (TEF25/PEF), were highest in 1 day old infants (medians 0.39, 0.46 and 0.81 respectively), decreasing to a minimum in 4-5 day old infants, but were not influenced by birthweight. Tidal flows and flow ratios were higher in males versus females, even after weight adjustment. Respiratory rates correlated significantly with tidal flows (r = 0.66), inversely with Vt (r = 0.40), but not with flow ratios. Mean compliance of the respiratory system was 1.18 ml.cmH2O-1.kg birthweight (95% confidence interval (95% CI) 1.15-1.21) and mean resistance 0.051 cmH2O.ml-1.s (95% CI 0.049-0.054). These results demonstrate that lung function in awake healthy infants varies according to weight, gender and postnatal age.(ABSTRACT TRUNCATED AT 250 WORDS)

Asthma↗

PubMed1994

Can the increasing weight of Australians be explained by the decreasing prevalence of cigarette smoking?

In Australia there has been a recent increase in the body mass index (BMI) of the population and a decrease in smoking prevalence. Data from the three risk factor prevalence surveys conducted by the National Heart Foundation of Australia in 1980, 1983 and 1989 were analysed to determine if the increase in BMI could be explained by the decrease in smoking. For men in all age groups and for women aged 50 years or over, there were parallel increases in mean BMI for current smokers, ex-smokers and never smokers. For women under 50 years, the pattern of increasing BMI over time was less clear. Mean BMI increased over time within each five-year age group and in age 'cohorts' and the pattern was independent of smoking status. For men and for both groups of women there were similar changes in mean BMI over time for most categories of employment status, education and physical activity. Thus the increase in body weight cannot be explained by the decrease in smoking rate, or by the other factors investigated in this paper.

Adult↗

PubMed1993

[Apparent decrease in the occurrence of anencephalus in Norway 1967-90].

The occurrence of anencephalus as reported to the Norwegian Medical Birth Registry has fallen from 4.9 per 10,000 births in 1967-71 to 2.7 in 1987-90. The decrease is particularly noticeable for births with a gestational length of 28 weeks or more. On the other hand, there has been a significant increase in the number of cases of anencephalus with a gestational age less than 28 weeks. The occurrence of meningomyelocele has remained relatively stable throughout the same period. Ascertainment error could explain these contrasting trends, since cases of anencephalus detected on ultrasound screening may lead to early termination of pregnancy without notification to the Medical Birth Registry. Better routines for notification of malformations are needed to improve the basis for surveillance in Norway.

Anencephaly↗

PubMed1993

[Mortality and causes of death among intravenous drug addicts in Oslo].

In order to study mortality and causes of death among intravenous drug users in Oslo, 1,009 (829 HIV negative and 180 HIV positive) intravenous drug users were followed from their first HIV test for a mean period of 36 months (range 1-67 months). 87 (55 HIV negatives and 32 HIV positives) died during the follow-up period. Compared with the general population with the same age and sex distribution, the relative risk of death for the intravenous drug users was 31. 4% of the HIV negatives (38/829) and 11% of the HIV positives (20/180) died from drug overdose during the follow-up period. 2% of the HIV positives and 0.4% of the total cohort (4/1,009) died from AIDS. Drug overdose represented the major threat to life among intravenous drug users in this study. Due to the dynamic of the HIV epidemic, AIDS may gain an increasing impact on mortality. However, in order to forecast the number of AIDS cases among intravenous drug users, it is necessary to control for the high non-AIDS related mortality.

Acquired Immunodeficiency Syndrome↗

PubMed1993

Differences in mortality rates and causes of death between HIV positive and HIV negative intravenous drug users.

In order to study differences in mortality and causes of death between HIV positive and HIV negative intravenous drug users (IVDU), 1009 (180 HIV positive and 829 HIV negative) IVDU in Oslo, Norway, were followed from their first HIV test for a mean period of 36 months (range 1-67 months). Eighty-seven (55 HIV negatives and 32 HIV positives) died during the follow-up period. The risk of death for IVDU was 31 times higher than for the general population. The estimated probability of survival after 3 years of follow-up was 0.92 for the whole cohort, 0.93 for the HIV negative group and 0.87 for the HIV positive group (P < 0.001, log rank test). In a Cox regression analysis, HIV positivity, > 30 years of age and > 5 years of IV drug use prior to study entry were all significantly associated with a fatal outcome. Eleven per cent (n = 20) of the HIV positives and 4% (n = 38) of the HIV negatives died from drug overdose, which accounted for 68% of all deaths; 2.2% of the HIV positives and 0.4% (n = 4) of the total cohort died from AIDS. Drug overdose represented the major threat to life among IVDU in this study. Because of the dynamics of the HIV epidemic, AIDS may have an increasing impact on mortality. However, in order to forecast the number of AIDS cases among IVDU the high non-AIDS mortality must be controlled for.

Adolescent↗

PubMed1993

Different effects of maternal and paternal education on early mortality in Norway.

In order to separate the effects of maternal and paternal education on pregnancy outcome, a total population of 97,526 single, firstborn infants and their parents was studied. Census information from 1980 was linked to the Medical Birth Registry for 1978-82. Children of parents with high education (> 12 years) were the most likely to survive the first year of life. There was a linear association between parental education and infant mortality. Examining parental education jointly, it was found that the father's educational level had the greatest impact on stillbirth. Mother's educational level seemed to be more closely associated with postneonatal mortality. Possible mechanism to explain the association between educational level and infant mortality are discussed.

Educational Status↗

PubMed1993

Temporal and regional trends in fatal childhood injuries in Norway 1971-1989.

The paper focuses on how mortality due to injuries among Norwegian children has varied over time and throughout the country over the last two decades. The temporal trends are compared to those of the other Nordic countries. Individual data on date of birth and death, county of residence at death, sex and cause of death were obtained from the Norwegian Death Registry on all children aged 0-14 who died during the time-span 1971-1989. Denominators were the number of persons alive in the corresponding age, year, sex and county groups. There has been a decline in fatal injuries from 25 to 9 deaths per 100,000 person-years in, respectively, 1971 and 1989. The decline is less distinct in the late 1980's. The rate of fatal injuries have throughout the period been lowest in the county of Oslo and highest in Northern Norway with fatal injury rates in Finnmark 3 times that of Oslo. The declining time trend was present for all types of injuries except bicyclists and passengers, but with the sharpest decline for pedestrians and drowning injuries. The regional variation was strongest for drowning and showed a different profile from the overall pattern for bicyclists, passengers and falling injuries. The incidence of fatal injuries in Norway is comparable to those of Denmark, Finland and Iceland, but considerably higher than in Sweden. In all Nordic countries the rates have declined to about one third from 1971 to 1988.

Adolescent↗

PubMed1993

The familial risk of endometriosis.

OBJECTIVE: To study the occurrence of endometriosis or adenomyosis in mothers and sisters of patients with endometriosis. METHODS: A total of 563 patients with endometriosis were interviewed about endometriosis or adenomyosis in their mothers or sisters. Five hundred and twenty-eight patients (94%) gave information about their relatives. Six patients were adopted and had no knowledge about their relatives. Among 522 patients were seven pairs of sisters, of which only one was included, giving a total of 515 cases. The control group consisted of 149 women without endometriosis documented at a recently diagnostic laparoscopy performed in connection with sterilization. The controls were likewise interviewed about their relatives, and none refused to give information. If a gynecological operation in a relative was reported, medical records were obtained (68%) or a description of the medical history was given by the proband. RESULTS: Endometriosis or adenomyosis was disclosed in 3.9% of mothers of cases and in 0.7% of mothers of controls, in 4.8% of sisters of cases and in 0.6% of sisters of controls. The relative risk of endometriosis in a first-degree relative (expressed as odds ratio), was 7.2 (95% confidence interval 2.1, 24.3). Severe manifestations of endometriosis were found more often among patients with a positive family history than among those without (26% versus 12%, p < 0.01). CONCLUSION: The study demonstrates a seven fold increased risk of endometriosis in mothers and sisters of patients with endometriosis. It is assumed that daughters of patients with endometriosis have a similar risk of developing endometriosis.

Adult↗

PubMed1992

Secular trends and sociodemographic regularities of coital debut age in Norway.

Gender and birth cohort differences and the influence of social background variables on the coital debut age were investigated in the general population of Norway. The data derive from a 1987 questionnaire on sexual behavior mailed to a random sample of 10,000 Norwegians of both sexes, ages 18 through 60; 63% responded to the questionnaire. 94.5% reported that they had experienced intercourse. The median coital debut age was 18.2 years. There were both cohort and gender differences. Younger cohorts have lower coital debut ages, and women younger than 35 years experienced their first intercourse at an earlier age than men in the same age group. When each independent variable was analyzed separately, there were substantial differences between educational levels and social classes with respect to age of coital debut. Multivariate analysis of six separate cohorts revealed independent effects of gender in the two youngest cohorts, whereas educational level had significant independent effects in all but the oldest cohort. Social class did not reveal any independent effect on coital debut age. Population density of the place of residence of the respondents was not substantially related to age of coital debut. Seen together, the independent variables explain about 13% of the variance in coital debut age (by multiple regression).

Adolescent↗

PubMed1992

Small-for-gestational-age (SGA) definitions and associated risks.

Samples and methods vary in constructing birthweight charts. Introduction of ultrasound dating affects the distribution of gestation, increases the proportion of preterm births, and reduces postterm and small-for-gestational-age (SGA) births. The need for standardized charts is emphasized. Preferably such charts ought to be sex- and parity-specific, also taking into account the mother's previous pregnancy outcome in terms of birthweight. The risks associated with being born SGA involve various morbidity as well as short- and long-term survival.

Female↗