Biomedical subjects

A Tverdal

Publications and source records attributed to A Tverdal.

At least 37 records · Page 2Linked to original sources

PubMed2000

Factors associated with mortality after hip fracture.

There is a well-known excess mortality subsequent to hip fracture, which is probably restricted to subgroups of hip fracture patients with reduced health status. We studied the association between risk factors and death in 248 hip fracture patients and 248 controls originally enrolled in a population-based case-control study. This cohort was followed for 3 1/2 years with respect to total mortality. A markedly increased mortality was found in hip fracture patients passing a mental status test at a low score [relative risk (RR) = 2.3, 95% confidence interval (CI) 1.4-3.7], in hip fracture patients reporting two or more selected chronic diseases (RR = 3.3, 95% CI 1.8-6.1), in hip fracture patients not walking outdoors before the fracture (RR = 3.2, 95% CI 2.0-5.1) and in hip fracture patients in the lower half of handgrip strength distribution (RR = 2.3, 95% CI 1.6-3.4), all compared with the control group. In contrast, hip fracture patients without these risk factors did not have increased mortality compared with the control group. This study suggests that otherwise healthy and fit patients do not have increased mortality subsequent to hip fracture. The excess mortality is restricted to persons with reduced mental status, reduced somatic health and low physical ability. Special attention should be paid to patients with such risk factors in the treatment and rehabilitation period.

Aged↗

PubMed2000

Plasma total homocysteine, pregnancy complications, and adverse pregnancy outcomes: the Hordaland Homocysteine study.

BACKGROUND: Total homocysteine (tHcy) measured in serum or plasma is a marker of folate status and a risk factor for cardiovascular disease. OBJECTIVE: Our objective was to investigate associations between tHcy and complications and adverse outcomes of pregnancy. DESIGN: Plasma tHcy values measured in 1992-1993 in 5883 women aged 40-42 y were compared with outcomes and complications of 14492 pregnancies in the same women that were reported to the Medical Birth Registry of Norway from 1967 to 1996. RESULTS: When we compared the upper with the lower quartile of plasma tHcy, the adjusted risk for preeclampsia was 32% higher [odds ratio (OR): 1. 32; 95% CI: 0.98, 1.77; P for trend = 0.02], that for prematurity was 38% higher (OR: 1.38; 95% CI: 1.09, 1.75; P for trend = 0.005), and that for very low birth weight was 101% higher (OR: 2.01; 95% CI: 1.23, 3.27; P for trend = 0.003). These associations were stronger during the years closest to the tHcy determination (1980-1996), when there was also a significant relation between tHcy concentration and stillbirth (OR: 2.03; 95% CI: 0.98, 4.21; P for trend = 0.02). Neural tube defects and clubfoot had significant associations with plasma tHcy. Placental abruption had no relation with tHcy quartile, but the adjusted OR when tHcy concentrations >15 micromol/L were compared with lower values was 3.13 (95% CI: 1.63, 6. 03; P = 0.001). CONCLUSION: Elevated tHcy concentration is associated with common pregnancy complications and adverse pregnancy outcomes.

Abruptio Placentae↗

PubMed2000

Pulmonary tuberculosis in Norwegian patients. The role of reactivation, re-infection and primary infection assessed by previous mass screening data and restriction fragment length polymorphism analysis.

SETTING: Norwegian patients with pulmonary tuberculosis notified to the National Tuberculosis Register in 1975, 1985 and 1995. OBJECTIVE: To assess the proportion of cases attributable to endogenous reactivation, exogenous re-infection and primary infection. DESIGN: We reviewed patients notified with sputum smear and/or culture confirmed pulmonary tuberculosis in 1975 (50% random sample, 95 cases), 1985 (133 cases) and 1995 (70 cases). Information on previous chest X-ray, tuberculin and BCG status was collected from mass screening data files. Strains from 54 patients in 1995 were analysed by IS6110 restriction fragment length polymorphism (RFLP) typing and compared with culture-positive patients notified between 1994 and 1997. RESULTS: Most patients had previously had tuberculosis (65% in 1975, 53% in 1985 and 61% in 1995), either notified with tuberculosis or with X-ray findings indicating previous tuberculosis. Another 10% had a prior infection, but normal X-rays. No previous tuberculosis infection or disease was found in 10% in 1975, 19% in 1985, and 16% in 1995. Of 54 patients with RFLP results, three were caused by laboratory contamination. Of the remaining 51, eight (16%) belonged to a cluster. Among 45 patients with results of both RFLP typing and mass screening, 37 (82.2%) were probably caused by reactivation, six (13.3%) by re-infection and two (4.4%) by primary infection. CONCLUSION: Pulmonary tuberculosis in Norwegian patients can mainly be attributed to reactivation, predominantly in persons with previous changes on chest X-ray.

Adolescent↗

PubMed1999

Reproduction management of tethered cows on Norwegian dairy farms.

Dairy farms in southern Norway were surveyed to obtain information regarding reproduction management in tied herds. A total of 1613 farms were included in the analyses. Reproductive performance during the main breeding period of the year (November 1 to February 28) was measured using the following dependent variables: calving to first service and last service interval, number of artificial inseminations per cow, non-return rate at 60 days, and calving interval. Culling for failure to conceive was found to be associated with longer calving to first service interval, more inseminations per cow and lower non-return rate. More inseminations per cow and lower non-return rate were also recorded in herds where breeding was close to calving. Oestrous checks late in the evening and frequent observations were associated with shorter calving to last service interval and shorter calving interval. Calving to last service interval was prolonged if the farmers were occupied with routine work while conducting oestrous checks. Manual rectal pregnancy testing was of little importance for reproductive efficiency in dairy herds with good breeding performance. More inseminations per cow occurred in herds where oestrous checks were conducted systematically 3 and 6 weeks after service. Calving to last service interval and calving interval were shorter when only one person was responsible for the herd breeding management.

Animal Husbandry↗

PubMed1999

[Food habits in Hedmark related to gender, education and marital status].

Several studies have shown a positive correlation between length of education and healthy dietary habits. This study examines associations between dietary habits and gender, length of education and marital status among adults in a Norwegian county. In 1997, all residents aged 40-42 (n = 7,870), in Hedmark County were invited to participate in the Age 40 Programme of the National Health Screening Service; 64% participated. Data on the consumption of selected foods were collected by a questionnaire. We found that relatively more women than men had fish at least once a week and fruit/vegetables and skimmed milk at least once a day. Women were also less likely to use butter on sandwiches. Comparing dietary habits with respondents' length of education, we found that a larger proportion of those with more education often had fish, fruit/vegetables and skimmed milk than did those with less education. The better educated were also more likely not to use butter/margarine on sandwiches. No clear correlation between marital status and dietary habits was found. The women in our study adhered more strictly to the recommended use of more fruit and vegetables and less fat than did the men, and the better educated group of respondents had dietary habits which were more in line with dietary recommendations.

Adult↗

PubMed1999

Foetal loss in dairy goats: function of the adrenal glands, corpus luteum and the foetal-placental unit.

To investigate the causes and mechanisms of foetal loss in Norwegian dairy goats, blood parameters in 40 goats that lost foetuses were compared with those in 40 goats that experienced a normal pregnancy. High mean levels of 15-ketodihydro-PGF2alpha, and low mean levels of oestrone sulphate throughout pregnancy were associated with foetal loss. The mean oestrone sulphate level was low before abortion, and the distinct peak that occurred at parturition in the control goats was not observed in connection with abortion. Association of other blood parameters with foetal loss was not detected. Infectious agents and toxins did not appear to be major causes of foetal loss in this study. The normal level of progesterone and cortisol in goats with foetal loss indicated that the function of the corpus luteum and adrenal glands, respectively, were not disturbed. The rapid decline in progesterone level associated with foetal loss may therefore be a result, rather than the cause, of foetal death. The lowered level of oestrone sulphate and elevated level of 15-ketodihydro-PGF2alpha in goats with foetal loss clearly indicated that the endocrine foetal-placental function was disturbed.

Abortion, Veterinary↗

PubMed1999

Calculation of risk for the development of acute myocardial infarction in the normal population based on long-term follow-up studies: smokers compared with non-smokers.

The objective was to study the association between smoking habits and mortality from coronary heart disease among men and women aged 35-49 years. Almost 45000 individuals (50% women) from three counties in Norway attended a screening programme during 1974-1978. The participation rate was almost 90% of the population. These individuals have been followed for an average of 18 years through the Norwegian death register. There were 1021 and 193 deaths from coronary heart disease among men and women, respectively. The mortality rate among current smokers was three times higher than that among those who had never smoked cigarettes. The relative risk between low-dose smokers and non-smokers was higher than that between high- and low-dose smokers. Among men, the relative risk between smokers and non-smokers was lower in the age group 45-49 years than in the two younger 5-year age groups. Among women, the relative risks did not vary significantly across the age groups. The relative risk between smokers and non-smokers remained the same in the first and second half of the observation period in men. A stronger association in the second half of the observation period was suggested among women (P = 0.08). The duration of smoking was an independent predictor of coronary heart disease among men, but not among women. Duration of smoking and length of follow-up seemed to have a different relationship with mortality from coronary heart disease in men and women. The dose-response relationship was the same in men and women, on the relative scale. Age affected the magnitude of relative risk between smokers and non-smokers among men, but not among women.

Adult↗

PubMed1999

Rapid changes in the prevalence of obesity and known diabetes in an adult Norwegian population. The Nord-Trøndelag Health Surveys: 1984-1986 and 1995-1997.

OBJECTIVE: To determine whether changes in mean BMI and the prevalence of obesity in a total adult population during a short (11-year) period were associated with changes in the prevalence of diabetes. RESEARCH DESIGN AND METHODS: This study involved cross-sectional surveys of all inhabitants aged > or = 20 years of the county of Nord-Trøndelag from 1984 to 1986 (n = 85,100) and from 1995 to 1997 (n = 92,434). Attendance rates were 88.1 and 71.3%, respectively, and 90.0% in an additional survey of people aged 13-19 years from 1995 to 1997 (n = 9,593). Main outcome measures were age-specific mean BMI for the diabetic and nondiabetic subgroups and the prevalence of obesity and diabetes. For comparison, mean BMIs from 18 of 19 Norwegian counties for the group aged 40-42 years were examined. RESULTS: Mean BMI increased from 27.2 to 29.0 kg/m2 in the diabetic population and from 25.1 to 26.3 kg/m2 in the nondiabetic population. The BMI distribution curve shifted to the right, but homogeneity was also reduced. A comparison with other Norwegian counties indicated that this increase occurred during the last 6 years between the surveys. The prevalence of obesity (BMI > or = 30 kg/m2) increased from 7.5 to 14% in nondiabetic men and from 13 to 18% in nondiabetic women. The increase was particularly great in men aged < 60 years and in women aged < 50 years. The overall prevalence of known diabetes increased between the two surveys (from 2.9 to 3.2%) but only in men. The largest increase was observed in the corresponding younger sex and age-groups. CONCLUSIONS: A substantial increase in mean BMI and the prevalence of obesity occurred in the younger age-groups at the same time as an increase in the prevalence of diabetes. A greater increase in diabetes prevalence in this ethnically stable Western European population may follow if effective primary preventive strategies are not undertaken.

Adolescent↗

PubMed1999

Effects of photointensity and photoperiod on milk yield and reproductive performance of Norwegian red cattle.

Relationships between light exposure, milk yield, and reproductive traits in Norwegian Red cattle were studied using data from 1538 farms in southern Norway during the darkest part of the year (November 1 to February 28). Production level was expressed as milk yield at first artificial insemination (AI) and 305-d milk yield. Reproductive performance was calculated using the following dependent variables: age at first AI, age at first calving, days open, calving interval, number of AI per cow, and nonreturn rate at 60 d. Days open and calving interval were both 4.0 d shorter, number of AI per cow was 0.07 less, non-return rate was 3.1% greater, and daily milk yield at first AI was 0.5 kg greater in herds that used dim illumination at night compared with herds that used no illumination at night. Milk yield at first AI was 0.5 kg greater in herds with photoperiods > 12 h. Photoperiods > 12 h were associated with a reduction in age at first AI by 4.8 d and age at first calving by 6.6 d. We concluded that dairy cattle kept at high latitudes during winter should be exposed to dim illumination at night and a minimum photoperiod of 12 h to stimulate reproductive performance and milk yield.

Animals↗

PubMed1999

A comparative study of reproductive performance in organic and conventional dairy husbandry.

A comparative cohort study of reproductive performance in organic and conventional dairy husbandry was conducted using longitudinal data from the Norwegian National Board of Animal Production Recording from January 1, 1994 to December 31, 1996. The present study is the first study comparing reproductive efficiency in organic and conventional husbandry in which characteristics such as herd size, breeding season, milk yield, parity, breed, use of artificial insemination (AI), and geographical distribution were taken into account. The organically managed cohort comprised 998 lactation periods, and the conventionally managed cohort comprised 3016 lactation periods. Both groups were similar in herd size and geographical distribution. The following reproduction variables were studied: days open, calving interval, calving to first AI interval, calving to last AI interval, and AI per cow. No consistent difference in reproductive performance was found between the cohorts before adjustments were made for milk yield, breeding season, service, and parity. After inclusion of these independent variables in the repeated measures, mixed-model analyses, reproductive efficiency of organically managed dairy cows was impaired compared with those under conventional management. In organic dairy farming, breeding efficiency was difficult to maintain in cows bred during winter. Organic husbandry proved more efficient than did conventional husbandry in converting roughage into milk. Furthermore, the average multiparity percentage was higher in organically managed cows.

Animals↗

PubMed1998

Weight variability, weight change and the incidence of hip fracture: a prospective study of 39,000 middle-aged Norwegians.

There is an increased risk of hip fracture and low bone mass in thin individuals. An association between weight loss and hip fracture has also been reported. In addition, it has been suggested that weight cycling might lead to bone loss. We studied weight variability and change in 19,938 women and 19,151 men who all attended three consecutive health examinations during an average period of 12 years, and assessed the effect of these on the incidence of hip fracture during a subsequent follow-up. Mean age at start of follow-up was 48.6 years in women and 48.5 years in men. For each subject weight variability and linear trend in weight change between the three examinations were assessed by linear regression of weight versus time. The cohort was followed on average 11.6 years from the third examination with respect to hip fracture. During follow-up, 148 hip fractures were identified in women and 59 in men. In both sexes, those with most weight variability had increased risk of fracture (relative risk (RR) = 2.07, 95% confidence interval (CI) 1.24-3.46 in women, and RR = 2.70, 95% CI 1.25-5.86 in men, high vs low quarter of weight variability). Overall, the effect of weight variability was not affected by adjustment for body mass index and linear trend in weight change. In men, there was also an association between weight loss and hip fracture. In summary, high weight variability defined a group with increased risk of hip fracture in this middle-aged cohort. The effect was independent of body mass index and linear trend in weight change. Whether weight variability leads to increased risk of fracture per se or whether it defines a group with otherwise increased risk of fracture is not known, and needs further investigation.

Aged↗

PubMed1998

Serum lipids in postmenopausal or perimenopausal women using estrogen alone, estrogen with levonorgestrel, or estrogen with norethisterone, compared with nonusers: results from a cross-sectional study in two Norwegian counties 1985-1988.

The aim of this study was to compare, in a population setting of postmenopausal or perimenopausal women aged 40 to 54, the levels of serum lipids in women using different hormone replacement therapy (HRT) regimens with women using no sex hormones. There was no unequivocal tendency of a more healthy lifestyle among those using HRT than among nonusers. Any type of regimen was associated with a lower mean level of total and calculated low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol was 0.08 mmol/L (5.2%) higher in those using estrogen alone, 0.07 mmol/L (4.5%) higher in users of HRT with norethisterone, and 0.07 mmol/L (4.5%) lower in users of HRT with levonorgestrel, compared with nonusers. The ratio of total-to-HDL cholesterol was lower by 0.37 (6.1%) in those using estrogen alone, by 0.65 (12.3%) in those using HRT with norethisterone, and by 0.24 (5.3%) in those using estrogen with levonorgestrel. There was no association between body mass index and HDL-cholesterol among women who used HRT with norethisterone, whereas an inverse relationship was present in those using estrogen alone and in nonusers (P [interaction] < 0.05).

Adult↗

PubMed1997

Dietary factors and the incidence of hip fracture in middle-aged Norwegians. A prospective study.

Dietary data from a prospective study were used to relate factors influencing calcium balance (estimates of dietary calcium intake, protein intake from nondairy animal sources (meat, fish, and eggs), and coffee consumption) to the incidence of hip fracture. During the years 1977-1983, women and men born between 1925 and 1940 and living in one of three Norwegian counties were invited to a cardiovascular screening that included a dietary survey. The attendance rate at screening was 91.1%, and 90.7% of these persons (19,752 women and 20,035 men) filled in and returned a semiquantitative dietary questionnaire. This cohort was followed for an average of 11.4 years (range, 0.01-13.8 years) with respect to hip fracture, defined as cervical or trochanteric fracture. During follow-up, 213 hip fractures were identified, excluding fractures associated with high-energy trauma and metastatic bone disease. There was no clear association between calcium intake or nondairy animal protein intake and hip fracture in this cohort. However, an elevated risk of fracture was found in women with a high intake of protein from nondairy animal sources in the presence of low calcium intake (relative risk = 1.96 (95% confidence interval 1.09-3.56) for the highest quarter of nondairy protein intake and the lowest quarter of calcium intake vs. the three lower quarters of protein intake and the three higher quarters of calcium intake). Women who drank nine or more cups of coffee per day also had an increased risk of fracture, while there was no association between coffee consumption and hip fracture in men. Although these findings do not necessarily imply causal relations, they suggest the presence of risk factors for hip fracture that act through a negative calcium balance in this population.

Adult↗

PubMed1997

Foetal loss in dairy goats: an epidemiological study in 515 individual goats.

Effects of various factors pertaining to the individual goat on the reproductive performance were studied during one season in 515 pregnant dairy goats from seven herds. A significant difference in the risk of foetal loss was found between the herds. Advanced age, difficulty in conceiving, low social status, pregnancy with > or = 3 foetuses and previous foetal loss were significantly associated with current loss. No association was found between foetal loss and the current goat index, milk production last year, daily milk production at the time of dry-off and the presence or absence of horns or dehorning of the goat. The risk of foetal loss was not related to mating with specific bucks. No indication of relationship between goats with foetal loss was found by pedigree analysis including the sire, dam and dam's sire. However, the incidence of foetal loss was significantly higher in daughters of does that had suffered reproductive loss than in daughters of does without such a loss. This suggests a maternal or genetic influence on the occurrence of foetal loss. Culling of goats suffering non-infectious abortion and of their surviving progeny therefore seems reasonable.

Animal Husbandry↗

PubMed1997

Cohort study of ethnic group and cardiovascular and total mortality over 15 years.

Altogether, 3365 men and 3266 women who attended two cardiovascular screenings in 1974-1975 and 1977-1978, have been followed with respect to death for an average of 15 years. The mortality from coronary heart disease was lower in men who reported being of Lappish origin than in men who reported Norse origin at both screenings (Rate ratio: 0.38 [0.20-0.71]), when other major risk factors were taken into account. Among men without history of cardiovascular disease or symptoms of angina pectoris the rate ratio became 0.24 (0.09-0.63). With cardiovascular death as the endpoint, the corresponding rate ratios were 0.42 (0.25-0.73) and 0.31 (0.15-0.67). In women, a non-significant lower mortality was seen in the Lappish group than in the Norse group. This study is suggestive of some protection from coronary heart disease in middle-aged men of Lappish origin.

Adult↗

PubMed1997

Statistical aspects of fish vaccination trials.

Vaccine trials are performed to measure the efficacy of vaccines or vaccination strategies. The statistical aspects pertain both to design and analysis of such trials. In experimental trials, the design should ensure that the groups to be compared are equal in all respects except for the factor to be assessed. This is achieved by proper randomisation procedures. The diagnosis of cases should as far as possible be carried out without knowledge of vaccination status (blinding). If the administration of a vaccine per se is considered to influence the outcome, a similar administration of placebo in the control group should be considered. The required sample size will depend on a specified significance level, a specified power, and on the magnitude of the effect one wants to detect. If the cumulative numbers of cases in vaccinated and unvaccinated groups are registered at the end of the observation period, the effect can be measured by the risk ratio, risk difference or the relative percent survival. If the estimation is based on a fish-time approach and the presumption of constant rate of outcome over time is fulfilled, the rate ratio or the rate difference can be estimated. If the rate is not constant, the life table would be a method of choice. In the statistical analysis of the vaccination effect it is important to consider the assumptions on which the statistical tests are based. Proper choice of the experimental and statistical units in the trials is crucial. If a trial is set up with the individual fish as the statistical unit, adjusting for dependence (cluster effect) between the units may be indicated. If possible, the vaccine effect should be given by the point estimate and the confidence intervals. The statistical aspects of fish vaccination trials are based on general principles for controlled clinical trials, but they are also influenced by characteristics connected to the fish population and the experimental conditions.

Animals↗

PubMed1996

[Do people exercise less than they think?].

Physical activity is important for health. Physical inactivity is an independent risk factor for disease and speeds up aging. People say in health surveys that they exercise more than they did before. This does not conform with two important facts: Over the last 20 years people have reduced their calorie intake, but their weight is increasing. The only possible explanation is that they exercise less than before, probably because their daily life requires less and less physical activity. We believe this to be a serious health problem, and support the most recent recommendation: A daily walk for 30 minutes.

Aging↗

PubMed1996

[Risk factors of femoral neck fractures in Oslo].

In this matched case-control study from Oslo, risk factors for hip fracture were assessed in elderly non-institutionalized women and men. 246 hip fracture patients admitted to two hospitals in the course of one year were matched by sex and age to controls living in the catchment area of the hospitals We found increased risk of hip fracture in lean persons, in persons with self-reported weight loss because of poor appetite, and in persons with low food intake. One third of the hip fracture patients ate less than three slices of bread per day and one fourth ate less than three meals a day. We found no relation between calcium intake and hip fracture, whereas higher risk of fracture was suggested in persons with low vitamin D intake. Hip fracture was also associated with low levels of physical activity, low hand grip strength, smoking, low level of education, and frequent admissions to hospital prior to the study.

Aged↗