Biomedical subjects

Johan Svartberg

Publications and source records attributed to Johan Svartberg.

13 recordsLinked to original sources

PubMed2006

Endogenous testosterone levels and smoking in men. The fifth Tromsø study.

Smoking is a risk factor of coronary heart disease (CHD), while the role of testosterone in the development of CHD is controversial. The reported effects of cigarette smoking on testosterone levels in men are conflicting, and smoking may be an important confounding factor when evaluating the relationship between testosterone levels and CHD. Thus, the objective of the present study was to examine the associations of smoking status and number of cigarettes smoked per day with total and free testosterone levels in a cross-sectional population-based study of 3427 men participating in the fifth Tromsø study. Total testosterone, luteinizing hormone, follicle-stimulating hormone and sex hormone-binding globulin levels were measured with immunoassay while free testosterone levels were calculated. Waist circumference was also measured and two standardized questionnaires were completed, including smoking status and number of cigarettes smoked. The data were analysed with analysis of variance and covariance and multiple regression analysis. Smoking men had significantly higher levels of total and free testosterone compared with men who never smoked (p < 0.001 and <0.01 respectively). Both total and free testosterone levels increased significantly with increasing number of cigarettes smoked daily (p < 0.001). Smoking men had 15% higher total and 13% higher free testosterone levels compared with men who never smoked. Thus, smoking seems to be an important confounding factor when evaluating testosterone levels, and could possibly mask borderline hypogonadism.

Adult↗

PubMed2006

[Endogenous Cushing's syndrome].

BACKGROUND: Untreated endogenous Cushing's syndrome is a serious condition with high morbidity and mortality. New diagnostic procedures make today's assessment more accurate. We describe which tests should be done when there is suspicion of the syndrome. Treatment options are mentioned. MATERIAL AND METHODS: The paper is based on current international literature and reflects the experience of the authors. RESULTS AND INTERPRETATION: Endogenous Cushing's syndrome is caused by elevated cortisol levels. The reason can be overproduction of ACTH or an adrenocortical pathology. It should be considered when combinations of symptoms like central obesity, proximal muscle weakness, striae and menstrual irregularities are seen. Osteoporosis and impotence are other important symptoms. Diagnosis of Cushing's syndrome is often challenging. Measurement of urinary free cortisol or overnight dexamethasone suppression test has usually been performed initially. Midnight salivary cortisol seems promising as an alternative. The final diagnosis is often made after a combined evaluation of dynamic tests. The first-line treatment of endogenous Cushing's syndrome is surgery.

Adrenocorticotropic Hormone↗

PubMed2005

Neuropsychological function in relation to serum parathyroid hormone and serum 25-hydroxyvitamin D levels. The Tromsø study.

There are receptors for parathyroid hormone (PTH) and 1,25-dihydroxyvitamin D in the brain, and there are clinical and experimental data indicating that PTH and vitamin D may affect cerebral function. In the present study 21 subjects who both in the 5th Tromsø study and at a follow-up examination fulfilled criteria for secondary hyperparathyroidism (SHPT) without renal failure (serum calcium < 2.40 mmol/L, serum PTH > 6.4 pmol/L, and normal serum creatinine) and 63 control subjects were compared with tests for cognitive and emotional function. Those in the SHPT group had significantly impaired performance in 3 of 14 cognitive tests (Digit span forward, Stroop test part 1 and 2, and Word association test (FAS)) as compared with the controls, and also had a significantly higher depression score at the Beck Depression Inventory (BDI) (items 1-13). In a multiple linear regression model, a high serum PTH level was significantly associated with low performance at the Digit span forward, Stroop test part 1 and 2, and Digit Symbol tests. A low level of serum 25-hydroxyvitamin D was significantly associated with a high depression score. In conclusion, a deranged calcium metabolism appears to be associated with impaired function in several tests of neuropsychological function.

Adult↗

PubMed2005

[Should older men be treated with testosterone?].

BACKGROUND: Male hypogonadism is a clinical situation characterised by a low serum testosterone level in combination with a diversity of symptoms and signs such as reduced libido and vitality, decreased muscle mass, increased fat mass and depression. Similar symptoms in combination with subnormal testosterone levels are seen in some elderly men. Several publications have suggested that testosterone treatment in hypogonadal men may have beneficial effects, but it is still uncertain whether testosterone substitution in the aging man is indicated. Despite this uncertainty the sale of testosterone have increased enormously over the last few years, hence it seems important to discuss what we now know about such treatment. MATERIAL AND METHODS: Review of recent literature studying testosterone substitution in older men. RESULTS AND INTERPRETATION: The result from placebo-controlled studies of testosterone substitution in elderly men differ substantially, but it seems to improve, among other things, bone mineral density, body composition, perception of physical strength, and maybe libido. In the short term there have been few problems or complications with testosterone treatment, but effects on the cardiovascular system and the prostate over the long term remain uncertain. Before any general recommendation could be given, big prospective studies have to be performed. Treatment should, however, be considered in men with testosterone in the hypogonadal range accompanied by clinical symptoms. Treatment needs to be individualized and should preferably be initiated by specialists in andrology, endocrinology or urology.

Age Factors↗

PubMed2005

[Primary adrenal failure--causes, diagnostics and therapy].

BACKGROUND AND METHODS: An overview of primary adrenal failure with emphasis on replacement therapy is presented. The article is based on a review of recent literature and authors' personal experience. RESULTS AND CONCLUSIONS: Addison's disease is usually caused by an autoimmune destruction of the adrenal cortex. It is relatively rare (prevalence 14 per 100,000 inhabitants), but often considered as a differential diagnosis when evaluating fatigue, tiredness and loss of weight. Addison's disease is treated by repletion of glucocorticoids and mineralocorticoids. The recommended starting dose is 25 mg cortisone acetate per day divided into three (12.5 + 6.25 + 6.25 mg) or two doses (12,5 mg x 2). Mineralocorticoid replacement is given as fludrocortisone 0.05 - 0.2 mg in one dose per day. Treatment with 20 - 50 mg dehydroepiandrosterone has been studied in adrenal failure, but the evidence for positive effects is weak, and it can not be recommended as standard treatment in primary adrenal failure.

Addison Disease↗

PubMed2005

Serum parathyroid hormone as a predictor of increase in systolic blood pressure in men.

BACKGROUND: In cross-sectional studies there appears to be a link between calcium metabolism and blood pressure, and most studies have found a positive association between serum parathyroid hormone (PTH) and hypertension. OBJECTIVE: To determine the prognostic value of serum PTH regarding a future increase in blood pressure. DESIGN: A prospective cohort study. SUBJECTS: A total of 1784 individuals who had measurements of PTH in serum samples from both the fourth (1994) and fifth (2001) Tromsø studies, who did not use blood pressure medication during the observation period, and had serum calcium less than 2.61 mmol/l, were included. MAIN OUTCOME MEASURE: Delta blood pressure (blood pressure from 2001 minus blood pressure from 1994). RESULTS: The mean delta systolic blood pressure in the men and women during these 7 years was 5.8 and 8.1 mmHg, respectively. In a sex-specific linear regression model correcting for age, body mass index (BMI), and smoking status, serum PTH from 1994 was a significant predictor of delta systolic blood pressure in men (P < 0.01), but not in women. The difference in delta systolic blood pressure between those in the highest and those in the lowest PTH quartile was 3.5 mmHg. Similarly, delta serum PTH (serum PTH from 2001 minus serum PTH from 1994) was a significant predictor of delta systolic blood pressure in men (P < 0.05). CONCLUSIONS: Although these findings do not prove a causal relationship between PTH and blood pressure, it adds to the growing number of indications that PTH is involved in the development of hypertension.

Age Factors↗

PubMed2004

Waist circumference and testosterone levels in community dwelling men. The Tromsø study.

To examine the relationship of total and free testosterone and sex hormone-binding globulin (SHBG) with central obesity in men, we studied 1548 men aged 25-84 years that took part in the 1994--1995 survey of the Tromsø study. Total testosterone and SHBG were measured by immuno-assay and the free testosterone fraction was calculated. These measurements were analyzed in relation to anthropometric data and lifestyle factors. The age-adjusted correlation between waist circumference (WC) and total testosterone was -0.34 (p < 0.001), between WC and free testosterone -0.09 (p < 0.001) and, between WC and SHBG -0.44 (p < 0.001). Adjusting for BMI and lifestyle factors weakened, but did not eliminate these associations. All hormone and SHBG associations were stronger for WC than for waist-hip ratio or BMI. In age- and BMI-adjusted analyses men with a WC > or = 102 cm had significantly lower levels of total testosterone and SHBG compared to men with an optimal WC, defined as < 94 cm (12.3 vs. 13.9 nmol/l; p < 0.01 and 48.5 vs. 55.1 nmol/l; p < 0.001, respectively). The lowest levels of total and free testosterone were observed in men with relatively high WC despite relatively low overall obesity (BMI), suggesting that WC should be the preferred anthropometric measurement in predicting endogenous testosterone levels.

Adult↗

PubMed2004

Endogenous sex hormones in relation to age, sex, lifestyle factors, and chronic diseases in a general population: the Tromsø Study.

The role played by endogenous hormones in many diseases makes it important to understand factors influencing their levels. This study examined the distribution of total and free estradiol, FSH, and dehydroepiandrosterone sulfate (DHEAS) by age and sex and associations of these hormones with body mass index (BMI), lifestyle factors, and chronic diseases. Plasma samples taken from 1555 men and 1952 women 25-84 yr of age in 1994-1995 Tromsø Study were analyzed in 2001. Total estradiol increased with age among men (P < 0.001), with or without adjustment for BMI and lifestyle factors. FSH increased with age both in men (P < 0.001) as well as pre- (P < 0.001) and postmenopausal women (P = 0.01) after similar adjustment, and DHEAS decreased with age in both sexes (P < 0.001). With increasing BMI, free estradiol increased in men (P = 0.004), total and free estradiol increased in postmenopausal women (P < 0.001), and FSH decreased in men (P = 0.03) and postmenopausal women (P < 0.001). Men with chronic diseases had lower levels of DHEAS, compared with healthy men (P < 0.001). Smokers had higher DHEAS levels than nonsmokers. Further studies are needed to confirm these hormonal changes with age and disease.

Adult↗

PubMed2004

Association of endogenous testosterone with blood pressure and left ventricular mass in men. The Tromsø Study.

OBJECTIVE: To test the hypothesis that lower endogenous testosterone levels are associated with higher blood pressure, left ventricular mass, and left ventricular hypertrophy. DESIGN: Population-based cross-sectional study. METHODS: Sex hormone levels, measured by immunoassay, anthropometric measurements and resting blood pressure were studied in 1548 men aged 25-84 Years; echocardiography was completed in 1264 of these men. Partial correlations and multiple regressions were used to estimate the associations between sex hormones, blood pressure and left ventricular mass by height. Analyses of variance and covariance were used to compare men with categorical hypertension and left ventricular hypertrophy. RESULTS: In age-adjusted partial correlations, total testosterone and sex hormone-binding globulin (SHBG) were each inversely associated with systolic blood pressure (SBP) (P<0.001). Men with categorical hypertension (SBP> or =140 or diastolic blood pressure (DBP)> or =90 mmHg) had lower levels of total and free testosterone and SHBG before (P<0.001, P=0.011 and P<0.001, respectively) and after (P<0.001, P=0.035 and P=0.002, respectively) adjusting for body mass index (BMI). Total testosterone and SHBG were each inversely associated with left ventricular mass (P<0.001), and men with left ventricular hypertrophy had significantly lower levels of total testosterone (P=0.042) and SHBG (P=0.006); these associations were no longer significant after adjusting for BMI. CONCLUSION: The results of the present study are consistent with the hypothesis that lower levels of testosterone in men are associated with higher blood pressure, left ventricular mass, and left ventricular hypertrophy. The reduced associations after adjusting for BMI suggest that the association of low testosterone levels with blood pressure and left ventricular mass is mediated by obesity.

Aged↗

PubMed2003

[Hormonally inactive pituitary adenomas].

BACKGROUND: This paper surveys hormonally inactive pituitary tumours on the basis of the current international literature; it also reflects the experience of the authors. INTERPRETATION: Pituitary tumours are frequently diagnosed and usually show a low potential for growth. Although benign they may invade adjacent structures such as the cavernous and sphenoid sinuses. The diagnosis is usually made on the basis of pituitary failure or visual problems, or incidentally. Tumour debulking or removal, usually by transsphenoidal surgery, is indicated if there is a compression of the optic chiasm or if the tumour shows signs of growth on consecutive MRI scans. Surgery is an effective treatment of these tumours, with little risk of complications. Repeated surgery, either transsphenoidally or by craniotomy, is indicated if chiasmal decompression is not achieved initially. Fractionated single beam irradiation or stereotactic radiosurgery is indicated in cases where there is a residual of growing tumours that may not be removed surgically.

Acromegaly↗

PubMed2003

Seasonal variation of testosterone and waist to hip ratio in men: the Tromsø study.

Studies of seasonal variation in male testosterone levels show contradictory results. We report here a cross-sectional study of the seasonal variation in total and free testosterone, LH, and SHBG levels in 1548 men living in north Norway, a population exposed to a wide seasonal variation in temperature and daylight. Total testosterone showed a bimodal seasonal variation (P < 0.001) with a small peak in February, the nadir in June, and a more prominent peak in October and November. Free testosterone also showed a significant seasonal pattern (P < 0.001), with the peak in December and the nadir in August. These patterns persisted after adjusting for age and waist to hip ratio (P < 0.001). Lowest testosterone levels occurred in months with the highest temperatures and longest hours of daylight. Waist to hip ratio paralleled the change in daylight and temperature, with the highest values during the summer and was thus inversely related to the seasonal testosterone variation. The variations in hormone levels were large, with a 31% difference between the lowest and highest monthly mean level of free testosterone. Prospective studies are needed to establish the direction of the association and its etiology.

Adult↗

PubMed2003

The associations of age, lifestyle factors and chronic disease with testosterone in men: the Tromsø Study.

OBJECTIVE: To study whether lifestyle factors and/or chronic disease are associated with the age-related decline of total and free testosterone in men, or if these factors might be associated with the variation of total and free testosterone but not with their age-related decline. DESIGN: A population-based, cross-sectional study was used. METHODS: Total testosterone and sex hormone binding globulin (SHBG) levels were analyzed and free testosterone levels were calculated in 1563 men participating in the Tromsø study in 1994/1995. Anthropometric characteristics were also measured and two standardized questionnaires completed, including lifestyle factors and medical history. The data were analyzed with multiple linear regression analysis of covariance, and logistic regression. RESULTS: Total and free testosterone were inversely associated (P=0.001 and P<0.001), while SHBG was positively associated (P<0.001) with age. Body mass index (BMI) was inversely associated with total (P<0.001) and free (P=0.016) testosterone and SHBG (P<0.001). Both total and free testosterone were positively associated with tobacco consumption (P<0.001 and P=0.004) and total testosterone was positively associated with coffee consumption (P<0.001). SHBG was positively associated with smoking (P=0.004) and coffee consumption (P<0.001). Men who reported having had a stroke or having a cancer diagnosis had lower levels of total testosterone (P<0.001 and P<0.01) and free testosterone (P<0.01). CONCLUSIONS: BMI and smoking are independent contributors to the variation of total and free testosterone and SHBG levels, and coffee consumption to the variation of total testosterone and SHBG. Thus, lifestyle factors can have a direct effect on circulating levels of free endogenous sex hormones and to total levels due to the effect on SHBG levels.

Adult↗

PubMed2002

[Hyperprolactinemia and prolactinemia--investigation and treatment].

BACKGROUND: Prolactinoma represents the most commonly occurring hormone-secreting pituitary adenoma. The majority of prolactinomas are small, only rarely do we find larger prolactinomas, so-called macroadenomas. They are almost exclusively benign. The symptoms are mainly caused by elevated prolactin levels and result in changes to the reproductive and sexual function. In cases of macroprolactinomas, symptoms caused by local mass effects can be seen. A variety of other conditions may also cause hyperprolactinaemia; the goal of the examination is to identify the cause. MATERIAL AND METHODS: We have reviewed recent literature and compared findings with current management of hyperprolactinaemia and prolactinoma in Norwegian university hospitals. RESULTS AND INTERPRETATION: The primary treatment is medical, intended to normalize prolactin levels, restore gonadal function, and reduce tumour size. With the new selective dopamine agonists, the treatment is often simple and efficient, but not all patients are in need of treatment.

Adenoma↗