Anne Tollan

The Tromsø Study: Physical Activity and the Incidence of Fractures in a Middle-Aged Population

We have studied the relation of occupational and recreational physical activity to fractures at different locations. All men born between 1925 and 1959 and all women born between 1930 and 1959 in the city of Tromsø were invited to participate in surveys in 1979–1980 and 1986–1987 (The Tromsø Study). Of 16,676 invited persons, 12,270 (73.6%) attended both surveys. All nonvertebral fractures (n = 1435) sustained from 1988 to 1995 were registered in the only hospital in the area. Average age in the middle of the follow‐up period (December 31, 1991) was 47.3 years among men and 45.1 years among women, ranging from 32 to 66 years. Fracture incidence increased with age at all locations among women, but it decreased with or was independent of age among men. Low‐energetic fractures constituted 74.4% of all fractures among women and 55.2% among men. When stratifying by fracture location, the most physically active persons among those 45 years or older suffered fewer fractures in the weight‐bearing skeleton (relative risk [RR] 0.6, confidence interval [CI] 0.4–0.9, age‐adjusted), but not in the non–weight‐bearing skeleton (RR 1.0, CI 0.7–1.2, age‐adjusted) compared with sedentary persons. The relative risk of a low‐energetic fracture in the weight‐bearing skeleton among the most physically active middle‐aged was 0.3 (CI 0.1–0.7) among men and 0.9 (CI 0.4–1.8) among women compared with the sedentary when adjusted for age, body mass index, body height, tobacco smoking, and alcohol and milk consumption. It seems that the beneficial effect on the skeleton of weight‐bearing activity is reflected also in the incidence of fractures at different sites.

Rural doctor recruitment: does medical education in rural districts recruit doctors to rural areas?

Summary. The impact of the University of Tromsø Medical School on the distribution of doctors in rural areas in northern Norway was evaluated by a postal questionnaire. The survey covered 11 graduation years (417 doctors), and the response rate was 84.2%. The establishment of a new medical school in northern Norway has clearly had beneficial effects: a total of 56.1% of the graduates stay in these remote areas. Of those who also spent their youth in northern Norway the proportion is 82.0%, compared to graduates who lived in the southern parts of the country while growing up (37.7%). The results clearly demonstrate that one of the main goals for the Medical School at the University in Tromsø, to educate doctors who prefer to work in these rural areas, has been accomplished.

What do Norwegian women and men know about osteoporosis

A survey of a random sample of 1514 Norwegian women and men aged 16–79 years was undertaken to investigate knowledge of osteoporosis and attitudes towards methods for preventing this disease. The interviews were carried out by Central Bureau of Statistics of Norway as part of their monthly national poll using a structured questionnaire. Women knew more about osteoporosis than did men (p<01). In both men and women increased knowledge of osteoporosis was correlated to a high level of education. Furthermore it was clearly demonstrated that knowing someone with osteoporosis or suffering from it oneself increased the knowledge of osteoporosis significantly in both women and men. Multiple regression analysis confirmed the univariate analyses, and education was the strongest predictive factor for knowledge. To a hypothetical question as many as two-thirds of the women answered that they would use long-term hormone replacement therapy (HRT) to prevent osteoporosis on the recommendation of their general practitioner. Their attitudes towards the use of estrogen therapy did not show any significant relation to age, but their reluctance towards HRT increased with education (p<001). When asked a question about their preferences regarding the use of physical activity as a means to prevent osteoporosis, older women preferred walking (p<.001), whereas younger women wanted more organized athletic activity (p<001). The data demonstrated that there was a high degree of general knowledge of osteoporosis and its consequences in the general population.

The Tromsø Study: Body Height, Body Mass Index and Fractures

Abstract: Tall persons suffer more hip fractures than shorter persons, and high body mass index is associated with fewer hip and forearm fractures. We have studied the association between body height, body mass index and all non-vertebral fractures in a large, prospective, population-based study. The middle-aged population of Tromsø, Norway, was invited to surveys in 1979/80, 1986/87 and 1994/95 (The Tromsø Study). Of 16 676 invited to the first two surveys, 12 270 attended both times (74%). Height and weight were measured without shoes at the surveys, and all non-vertebral fractures in the period 1988–1995 were registered (922 persons with fractures) and verified by radiography. The risk of a low-energy fracture was found to be positively associated with increasing body height and with decreasing body mass index. Furthermore, men who had gained weight had a lower risk of hip fractures, and women who had gained weight had a lower risk of fractures in the lower extremities. High body height is thus a risk factor for fractures, and 1 in 4 low-energy fractures among women today might be ascribed to the increase in average stature since the turn of the century. Low body mass index is associated with a higher risk of fractures, but the association is probably too weak to have any clinical relevance in this age category.

The Tromsø Study: Registration of Fractures, How Good are Self-reports, a Computerized Radiographic Register and a Discharge Register?

Abstract: In order to compare different methods of fracture registration, we sought all nonvertebral fractures suffered during 8 years (1988–95) among 21 441 persons invited to a survey in 1979/80. We registered a total of 54 hip fracture cases through three separate sources (self-report, computer linkage to the local radiographic archives, discharge register), whereas forearm fractures (a total of 291 cases) were registered through two separate sources (self-report, computer linkage to the radiographic archives). The registration of fractures at other sites (a total of 1321 cases) were from one source (computer linkage to the local radiographic archives), and we have compared three ways of obtaining data from this single source (no ascertainment, ascertainment of records coded as fracture, ascertainment of all records). Ninety-three percent of all hip fractures and 97% of all wrist fractures in the entire study population were found by computer linkage to the radiographic archives, whereas the discharge register detected 87% of all the hip fractures. Computer linkage with ascertainment gave no overreporting of fractures. Among the 11 626 persons who answered a follow-up questionnaire in 1994/95, 97% (CI 84–100%) of all hip fractures and 72% (CI 66–78%) of all wrist fractures were self-reported. We conclude that a computerized search of radiographic archives is a viable method of fracture registration.

The Tromsø Study: Artifacts in Forearm Bone Densitometry – Prevalence and Effects

Abstract: Suboptimal performance of bone densitometer, operator and/or subject may cause artifacts of consequence both for individual patient management and research. The prevalence and effects of such artifacts are largely unknown in densitometry. A cross-sectional population-based study was carried out of artifacts in forearm bone densitometry with single X-ray Absorptiometry (SXA) of the nondominant hand (distal and ultradistal site). After the screening, all scans were reviewed for artifact detection and reanalysis. The effect on the bone mineral density (BMD) result was found by comparing artifactual scans with a reanalyzed version or with normal repeat scans. All women aged 50–74 years, all men aged 55–74 years and 5–10% samples of other age groups aged ≥25 years attending the fourth Tromsø health study were invited to have bone densitometry. The response rate from the background population was 80% (n= 7948). Fourteen percent of subjects had a movement artifact at either the distal or ultradistal site. The individual BMD variation was twice as large in scans with a movement artifact (0.94%) compared with normal scans (0.58%) (p= 0.0027). The radial endplate was inaccurately detected in 74% of the scans. Reanalysis of these scans led to a mean 3.8% decrease in the BMD value and an increase in the prevalence of osteoporosis of 10%. Artifacts were thus common, and their effects were clinically relevant in forearm bone densitometry. Artifacts and their effects need to be characterized in other bone densitometry settings also.

The Tromsø study: determinants of precision in bone densitometry.

Studies of precision determinants in bone densitometry are scarce. A total of 111 subjects recruited from the population-based multipurpose Tromsø Study (Norway), 27-75 years of age, had repeated forearm bone single X-ray absorptiometry (SXA) measurements. Measurement conditions were systematically varied in series up to eight scans. Median coefficients of variation (CV) for two scans performed 1 week apart, by two different operators were 0.79% and 0.98% at distal and ultradistal sites, respectively. The CV distribution was skewed: 5% of the subjects had individual CVs above 2.2% (distal) and 3.4% (ultradistal). Age (P = 0.0097) and repositioning were important determinants of precision. The SXA bone mineral density (BMD)-measurement method is sufficiently precise to establish BMD level. The minimal individual percentage BMD change that can be detected with 95% certainty was 2% and 3% at distal and ultradistal sites, respectively. Detection of BMD changes less than this should rely on multiple repeat measurements at each point in time.

Progesterone Reduces Sympathetic Tone without Changing Blood Pressure or Fluid Balance in Men

There is scant information on the effects of progesterone on circulation. Changes in catecholamine levels, blood pressure and transcapillary fluid balance were measured in 12 men before and during administration of natural progesterone (Utrogestan). Before administration, systolic blood pressure was significantly correlated with venous adrenaline (r = 0.67, p = 0.01). There was a significant decrease (p = 0.004) in venous noradrenaline during progesterone administration, and systolic blood pressure was significantly correlated with the arteriovenous difference for noradrenaline (r = 0.66, p = 0.02). Serum progesterone, which attained levels similar to those found in women during the luteal phase, did not significantly alter blood pressure, body weight or intra- to extravascular fluid shift. It is concluded that progesterone may have a direct action by increasing the uptake of noradrenaline from the synaptic cleft or by decreasing the nerve firing rate. Interestingly, the pretreatment finding of a significant correlation between blood pressure and adrenaline was less evident during progesterone administration.

Evidence for altered transcapillary fluid balance in women with the premenstrual syndrome

Redistribution of body fluids has been suggested us a possible pathophysiological mechanism for the premenstrual syndrome (PMS). To elucidate this hypothesis, transcapillary fluid balance was studied in ten women with well defined PMS. Wick‐methods were used for measuring colloid osmotic and hydrostatic interstitial pressures on the thorax and on the leg. The capillary filtration coefficient was measured by strain gauge plethysmography. From the follicular to the luteal phase the interstitial colloid osmotic pressure on the leg was significantly reduced (mean 3.6 mm Hg, p = 0.005), whereas the interstitial colloid osmotic pressure on the thorax remained constant. The capillary filtration coefficient increased 30% (mean 5.3 × 10−10 ml/min/100 gm/mm Hg, p = 0.04) from the follicular to the luteal phase. No change was observed in body weight. These findings indicate an instability of vascular regulation in women with premenstrual syndrome, and lend support to the hypothesis that redistribution of fluid, rather than water retention, is responsible for the subjective symptoms such as bloatedness, in the premenstrual syndrome.

Intrauterine device -- primary and secondary perforation of the urinary bladder.

Presented are two cases of Norwegian IUD acceptors with primary or secondary perforation of the uterus and bladder. The first patient a 43-year-old woman developed lower abdominal pain frequent micturition and dysuria 1 week after Nova-T IUD insertion. She was treated for a suspected urinary tract infection. When abdominal pain persisted transvaginal sonography was performed and revealed a strongly echogenic IUD located entirely in the urinary bladder. The device was moving freely within the bladder and easily removed through the cystoscope. Risk factors included a previous cesarean section with a scar in the anterior uterine wall and a very retroverted uterus. In the second case a Nova-T IUD was inserted in a 33-year-old woman 7 weeks after vaginal delivery. 7 months later she reported being unable to locate the IUDs strings. Transvaginal sonography indicated an IUD in the upper part of the uterine cavity but 2 attempts to remove the device failed. 1 month later a 2-plane x-ray located the IUD in the anterior upper part of the pelvic cavity. Since the patient felt no discomfort she declined laparotomy. 4 years later she presented with abdominal pain dysuria and recurrent urinary tract infections. Cystoscopy revealed the tail of the IUD the short strings and two-thirds of the shaft in the anterior upper part of the bladder. The IUD was easily removed through the cystoscope. Although it is a rare occurrence the possibility of bladder perforation should be considered when IUD users show persistent urinary symptoms.