High blood pressure is associated with decreased sensitivity to pain in humans and animals. Interestingly, hypoalgesia has also been observed in normotensive organisms at risk for hypertension, suggesting that it may be related to processes involved in the development of hypertension rather than with elevations of blood pressure per se. Sensitivity to laboratory and naturalistic daily aches and pains was assessed in young normotensive women and men with or without a parental history of hypertension and varying degrees of resting blood pressure. In women, risk for hypertension, as defined by a parental history of hypertension, relatively elevated systolic blood pressure, or a combination of the two, was associated with decreased pain reports and increased pain threshold for mechanical finger pressure, but not for the cold pressor test. Offspring of hypertensives also exhibited a reduced response to the pain stimuli compared to offspring of normotensives as assessed by the objective physiological measure of respiratory sinus arrhythmia (RSA). Group differences observed in the laboratory were generally maintained in reports of daily pain, with significant correlations emerging between laboratory and naturalistic pain reports. To assess the role of cardiopulmonary baroreceptor stimulation in blood pressure-related hypoalgesia, young men varying in risk for hypertension were exposed to finger pressure during a period of passive leg elevation and two control periods. Men with relatively elevated systolic blood pressure exhibited reduced pain during the period of leg elevation but not while in a supine position, nor following the valsalva manoeuver. The results of these studies support an association between risk for hypertension and pain sensitivity. This relation appears to extend to naturalistic pain encountered in daily life. Further, there is promising evidence suggesting that this relationship is influenced by cardiopulmonary baroreceptor activity.

A growing literature has reported a significant reduction in pain sensitivity among hypertensioe animals and humans. One of the key questions about this finding is whether a reduced sensitivity to pain can be observed in normotensive individuals who go on to develop high blood pressure. Blood pressure was re-assessed in one hundred and fifteen 19 year-old boys initially tested at age 14, when they were also presented with a pain stimulus (mechanical finger pressure). Analyses indicated that information regarding pain sensitivity improved prediction of changes in blood pressure beyond that afforded by differences in blood pressure at age 14, parental history of hypertension, and body mass index. Similar results were found in comparable analyses predicting 24-hour blood pressure recorded in one hundred and seventeen of the young men at age 22. Significant associations were also observed between pain sensitivity in 14 year-olds and 24-hour heart rate variability in various frequency bands at age 22, suggesting increased sympathetic and reduced parasympathetic tone among individuals less sensitive to pain. In order to further assess the relationship between autonomic function and pain sensitivity, one hundred and sixteen adolescent boys were assessed for pain sensitivity and autonomic responses to orthostatic challenge. Analyses indicated that exaggerated autonomic responses to postural change were associated with reduced pain sensitivity. Finally, to examine the potential role of endogenous opioids in blood pressure-related hypoalgesia, a group of young normotensive men were administered low-frequency transcutaneous electrical nerve 5 stimulation (TENS), which has been demonstrated to elicit endogenous opioid release, prior to being presented with two painful stimuli (electric shock and arm ischemia). A negative association between pain and resting blood pressure was significantly strengthened by administration of low-frequency TENS. The resu

Background: Many risk factors for venous thromboembolism have been identified, but two particular exposures - the use of combined oral contraceptives and long-distance air travel - have generated considerable concern in recent years. In contrast, a possible link between venous thromboembolism and a third exposure - the use of psychotropic drugs - was first raised in the 1950s, but has received surprisingly little attention. Information about all three exposures and the risk of fatal events is limited. These risks were examined in three inter-related national population-based studies. Methods: The underlying study population included all men and women aged 15 - 59 years who died in New Zealand between 1990 and 2000, for whom the underlying cause of death was pulmonary embolism. The potential associations between fatal pulmonary embolism and the use of oral contraceptives and psychotropic drugs were explored in a general practice records-based case-control study. Non-users were the reference category for all analyses. Contraceptive supply data were used to estimate the absolute risk of death from pulmonary embolism in users of oral contraceptives. A second case-control study, in which computer-assisted telephone interviews were undertaken with the next of kin of cases who had been resident in New Zealand, and with sex and age-matched controls randomly selected from the electoral roll, investigated the possible association between long-distance air travel and fatal pulmonary embolism. Finally, the absolute risk of dying from pulmonary embolism following a long-distance flight was estimated in a descriptive study based on official migration data and deaths in recent air travellers. Results: The adjusted odds ratio for use of any oral contraceptive in the three months before the index date (the onset of the fatal episode) was 13.1 (95% CI 4.4 - 39.0). The odds ratio for formulations containing desogestrel and gestodene was about three times higher than the point estimate for levonorgestrel products; preparations containing cyproterone acetate appeared to carry the highest risk. The estimated absolute risk of fatal pulmonary embolism in current users of oral contraceptives was 10.5 (95% CI 6.2 - 16.6) per million woman-years. The adjusted odds ratio for current use of any antipsychotic was 13.3 (95% CI 2.3 - 76.3). Low-potency antipsychotics carried a 20-fold increase in risk; thioridazine was the main drug involved. Antidepressant use was also associated with a significantly increased risk (adjusted odds ratio 4.9 [95% CI 1.1 - 22.5]). Compared with non-travellers, people who had undertaken a flight of more than eight hours� duration in the preceding four weeks were eight times more likely to die from pulmonary embolism (odds ratio 7.9 [95% CI 1.1 - 55.1]). The absolute risk of fatal pulmonary embolism following air travel of more than eight hours was 1.3 (95% CI 0.4 - 3.0) per million arrivals. Conclusions: The present research was the first to have estimated the relative risks of fatal pulmonary embolism in relation to three exposures: oral contraceptive use in a population in which preparations containing desogestrel and gestodene preparations were widely used, conventional antipsychotics, and long-distance air travel. The findings were consistent with previous, and subsequent, studies of non-fatal events. Increased risks of fatal pulmonary embolism in users of antidepressants, and in people with an intellectual disability, have not been described previously and warrant further investigation. Referral and diagnostic biases are very unlikely in these studies of fatal events, and other types of bias and possible confounding are considered unlikely explanations for the findings.

Background: As a multifactorial disease glaucoma may be associated with pressure-dependent and -independent factors. Ocular hypertension (OHT) may develop into primary open angle glaucoma (POAG) for many patients. We compared groups with OHT and POAG for pressure-dependent and -independent risk factors. A high prevalence of any factor(s) could indicate a contribution to progression from OHT to POAG. Method: A sample of patients with POAG (n 438) and with OHT (n 301) were selected from those attending a tertiary referral private glaucoma practice, and data were collected regarding age and intraocular pressure at the time of diagnosis, gender, family history of glaucoma, systemic hypertension, diabetes, Raynaud's phenomenon, migraine and myopia. Results: After multivariate analysis, older age at time of diagnosis (P<0.001), myopia (odds ratio (O.R) 1.5, 95percent confidence interval (C.I)1.0-2.2; P 0.05), a family history of glaucoma (O.R 1.6, 95 percent C.I 1.1-2.3; P 0.01) and a high intraocular pressure (P 0.002) were associated with POAG. No other significant differences were found between the two groups. Conclusion: Patients who have OHT may be at higher risk of developing POAG if they also have myopia, a family history of glaucoma or are of older age.

Diss. (sammanfattning) Umeå : Univ., 2006. / Härtill 4 uppsatser.

Diss. (sammanfattning) Umeå : Univ., 2006. / Härtill 5 uppsatser.

No description available.

No description available.

Stroke is a devastating, neurological dysfunction due to brain blood supply disturbance. It is responsible for increasingly high rate of mortality and disability worldwide. This thesis comprises two original studies involving 868 patients at risk of ischemic stroke and/or hemorrhagic stroke. The first study investigated aspirin’s effect among patients with intracranial hemorrhage. Unlike Caucasians which hemorrhagic strokes account for 10-15% of all strokes; in Chinese, intracranial hemorrhages strike up to 35%. After such, anti-platelet agent like aspirin is often avoided for fear of recurrent intracranial hemorrhages, despite compelling indications. However, clinical data is limited. In this single-centered observational study, we included 440 consecutive Chinese patients with a first spontaneous intracranial hemorrhage surviving the first month performed during 1996-2010. 56 patients (12.7%) of these 440 patients were prescribed aspirin after intracranial hemorrhage (312 patient-aspirin years). After a mean follow-up of 62.2 ± 1.8 months, 47 patients had recurrent intracranial hemorrhage(10.7%, 20.6 per 1,000 patient years). Patients prescribed aspirin did not have higher risk of recurrent intracranial hemorrhage compared with those without (22.7 per 1,000 patient-aspirin years vs. 22.4 per 1,000 patient years, p=0.70). Multivariate analysis identified age > 60 years and hypertension as independent predictors for recurrent intracranial hemorrhage. In a subgroup analysis: the incidence of combined vascular events including recurrent intracranial hemorrhage, ischemic stroke, and acute coronary syndrome was statistically lower in patients prescribed aspirin than without (52.4 per 1,000 patient-aspirin years, vs. 112.8 per 1,000 patient-years, p=0.04). Implications of the results: despite having a substantial risk for recurrent intracranial hemorrhage, post-intracranial hemorrhage ones are at risk for thrombotic vascular events and management goal should thus focus on ameliorating overall cardiovascular risk instead of preventing recurrent intracranial hemorrhage. Hence, thrombo-prophylaxis should still be considered. The second study investigated the relation between premature atrial complexes and new-onset atrial fibrillation together with other cardiovascular events. Premature atrial complexes though taken as benign phenomenon, are common in patients with underlying conditions such as coronary heart disease, chronic rheumatic heart disease. While prompt management of atrial fibrillation may prevent ischemic stroke, atrial fibrillation is often unfound until ischemic stroke occurs. In this study, 428 patients without atrial fibrillation but complained of palpitations, dizziness or syncope were recruited. 107 patients with >100 premature atrial complexes/day were defined to have frequent premature atrial complexes. After a mean follow-up of 6.1 ±1.3 years, 31 patients (29%) with frequent premature atrial complexes developed atrial fibrillation compared with 29 patients (9%) with premature atrial complexes?100/day (p<0.01). Cox regression analysis revealed: frequent premature atrial complexes, age>75 years and coronary artery disease were independent predictors. In secondary endpoint (ischemic stroke, congestive heart failure, and death), patients with frequent premature atrial complexes were more at risk than those without (34.5% vs. 19.3%) (Hazard ratio: 1.95, 95% confidence interval: 1.37-3.50, p=0.001). Cox regression analysis showed: age> 75 years, coronary artery disease and frequent premature atrial complexes were independent predictors. These permit early identification of high risks patients of new atrial fibrillation and other events, thus promoting appropriate preventive treatment. / published_or_final_version / Medicine / Master / Master of Philosophy

This study examined the relative risk of perinatal complications in common childhood disorders. Specifically, the ability of perinatal complications to predict membership into children's disorders was studied. The sample consisted of 634 normal children and children with mental retardation, learning disabilities, and emotional handicaps, whose mothers completed the Maternal Perinatal Scale (WS). Seven MPS items significantly contributed to the prediction of the mentally retarded, learning disabled, emotionally handicapped, and regular education groups. The two significant discriminant functions correctly classified about 46% of the students, with the greatest misclassification occuring for those with emotional handicaps. When the separate disorders were collapsed to form a single group, eleven MPS items significantly contributed to the prediction of the special education and regular education groups. The linear composite from discriminant function analysis correctly classified about 74% of the students. Some 89% of the special education students were correctly classified. When MPS factors were used as predictors, 90% of the special education students were correctly classified. Seven MPS factors comprised the discriminant function. Relative risk ratios were computed for each perinatal item. Significant relative risk ratios included maternal weight over 151 pounds, saddle block anesthesia, no anesthesia, stress during pregnancy, prenatal care, medically induced labor, unplanned pregnancy, medication use during pregnancy, hypoxia, and cigarette use during pregnancy. An overall relative risk of 6.35 was computed based on the linear composite of perinatal variables defined by the discriminant function, suggesting that a suggesting that a synergism of perinatal complications makes a child over 6 times more likely to be placed in special education. A second overall relative risk of 3.83 was derived from the linear composite of MPS factor scores. This indicated that children with a perinatal history marked by this particular combination of perinatal complications were nearly 4 times as likely to require special educational services. Results were discussed in terms of comorbidity among special education categories. The potential use of the MPS as a screener for early intervention was also discussed. / Department of Educational Psychology