Smoking Causes Fatal Subarachnoid Hemorrhage

Background and Purpose: One of the largest twin studies to date suggested that subarachnoid hemorrhage (SAH) is mainly of nongenetic origin, but the causal effect of environmental factors on SAH is yet unknown. We hypothesized that if only one of the twins experience fatal SAH, they do not share the most important environmental risk factor for SAH, namely smoking. If true, such finding would suggest that smoking causes SAH. Methods: Through the nationwide cause-of-death register, we followed 16 282 same-sex twin pairs of Finnish origin from the older Finnish Twin Cohort between 1976 and 2018 and identified all participants who died from SAH. For the baseline, we collected risk factor information about smoking, hypertension, physical activity, body mass index, alcohol consumption, and education. We classified the pairs as monozygotic, dizygotic, or of unknown zygosity. We examined the within-pair risk factor differences in the pairs discordant for SAH, that is, where one twin died from SAH and the other did not. We computed both individual (whole cohort) and pairwise (discordant pair) hazard ratios and 95% CIs. Results: During the 869 469 person-years of follow-up, we identified 116 discordant and 2 concordant (both died from SAH) twin pairs for fatal SAH. Overall, 25 of the discordant twin pairs were monozygotic. For the whole cohort, smoking (occasional/current) was associated with increased risk of SAH death (hazard ratio, 3.33 [CI, 2.24–4.95]) as compared with nonsmokers (never/former). In the pairwise analyses for discordant twin pairs, we found that the twin who smoked had an increased risk of fatal SAH (hazard ratio, 6.33 [CI, 1.87–21.4]) as compared with the nonsmoking twin. The association remained consistent regardless of the twin pairs’ zygosity or sex. Conclusions: Our results provide strong evidence for a causal, rather than associative, role of smoking in SAH.

Life events as predictors for disability pension due to musculoskeletal diagnoses: a cohort study of Finnish twins

Purpose Musculoskeletal diagnoses (MSD) are one of the largest diagnostic groups for disability pensions (DP). This study investigated the associations between life events and DP due to MSD, considering sociodemographic, health, and familial factors. Methods The study sample included 18,530 Finnish twins, 24–64 years old at baseline, who responded to a questionnaire in 1981 including a 21-item life event inventory. Information on DP with diagnosis codes (ICD codes: M00–M99) were obtained from the official national pension registers. Life events were divided into family- and work-related events. “Positive change in life” was analyzed separately. Cox proportional hazards models were used to calculate hazard ratios (HR) with 95% confidence intervals (CI). Results During the follow-up of 23 years, 1273 (7%) individuals were granted DP due to MSD. In discordant pair analysis, family-related events (≥ 4 events) increased (HR 1.63, 95% CI 1.31, 2.03) and the absence of such events decreased (HR 0.68, 95% CI 0.48, 0.95) the risk of DP due to MSD. For work-related events (≥ 3 events), the risk estimates were non-significant when controlling for familial factors. Having had a positive change in life decreased the risk of DP due to MSD (HR 0.79, 95% CI 0.65, 0.96) while controlling for familial confounding, but were non-significant in the full model controlling for various covariates (HR 0.91, 95% CI 0.75, 1.12). Conclusions The associations between life events and the risk of DP due to MSD are complex and potentially affected by familial and other confounding factors including sociodemographics and health.

Comparison of Student Performance on Internally Prepared Clerkship Examinations and NBME Subject Examinations

Background: This pilot study compared performance of University of Calgary students on internal clerkship examinations with corresponding National Board of Medical Examiners (NBME) subject examinations.Methods: Between April and October 2007, students completed internal and NBME subject examinations following six mandatory rotations. Local faculty within each discipline set the minimum performance level (MPL) for internal examinations. Two methods of standard setting were considered for NBME exams and a sensitivity analysis was performed. Corresponding internal and NBME examination scores were compared using McNemar’s discordant pair analysis.Results: A significant and unexpected difference in failure rate between internal and external examinations was found in all clerkships. 1.4% of students were below the MPL for internal examinations and 27.3% (modified Angoff) or 25.9% (mean Hofstee compromise) (p<0.0001 for both) for the NBME. The proportion of students below MPL for internal examinations was also below the lower limit of the Hofstee compromise (14.4%).Conclusion: Possible explanations include leniency bias in internal standard setting, discrepant content validity between local curriculum and NBME examinations, difference in student perception of examinations, and performance bias due to unfamiliar units.

Perinatal Risk Factors for Hay Fever — A Study Among 2550 Finnish Twin Families

Previous studies have suggested that perinatal factors influence the risk for asthma but population studies on perinatal factors and risk for hay fever are few. We studied the effect of perinatal factors on the risk for hay fever among adolescent twins by a questionnaire study involving five consecutive nation-wide birth cohorts of 16-year-old twins and their parents. The risk for parent-reported, doctor-diagnosed hay fever in the adolescents associated with several perinatal characteristics was assessed with logistic regression analysis among individuals and by a discordant pair analysis. In the univariate analysis of the birth factors, the risk for hay fever increased with increasing birth weight (p for trend = 0.048, OR for those ≥ 3000g 1.35, 95% CI 0.91–2.02 compared to those < 2000g) and gestational age (p for trend = 0.04, OR for those born after 40 weeks of gestation 2.24, 95% CI 1.03–4.86, compared to those born before 33 weeks of gestation) and was lower in those subjects hospitalised in the neonatal period (OR 0.74, 95% CI 0.58–0.93). Because of significant interactions between parental hay fever status and birth factors (ponderal index, p = 0.03 and maternal age p = 0.04), stratified analysis were performed. The positive association between birth weight and hay fever was most obvious among adolescents with no parental history of hay fever (p for trend = 0.03). Similar, though not significant, trends were found with other birth factors among these families, whereas no such trend was found among adolescents with parental hay fever, suggesting that gestational maturity increases the risk for hay fever in the absence of genetic predisposition. However, of the perinatal factors only neonatal hospitalisation (OR 0.75, 95% CI 0.59–0.96) remained a significant risk factor for the development of hay fever, when adjusted for non-perinatal factors.

Usefulness of the Neurobehavioral Cognitive Status Examination in the Hospitalized Elderly

A prospective pilot study compared the Neurobehavioral Cognituve Status Examination (NCSE) to the Folstein Mini-Mental State Examination (MMSE) to determine the usefulness of the NCSE as a cognitive screen in a geriatric inpatient population. All patients directly admitted to the geriatric evaluation and treatment unit (GETU) of a university teaching hospital over a two-and-a-half-month period were eligible for the study, in which 42% participated, Within 72 hours of admission, patients were given the MMSE and the NCSE in a nonrandom order by a trained psychologist and a structured interview by a psychiatrist. The ability of the NCSE to detect global cognitive impairment was compared to the MMSE and psychiatrist's assessment. Differences in sensitivity were examined by discordant pair analysis. The psychiatrist's determination of the presence of cognitive impairment was used as the criterion standard. Comparison of the MMSE and NCSE, respectively, revealed the following: sensitivity 83% versus 100%; specificity 78% versus 11%; positive predictive value 83% versus 43%; and negative predictive value 78% versus 100%. Seven patients who were cognitively impaired by the NCSE were not impaired by the MMSE (p < 0.05 by discordant pair analysis). The time of administration for the two tests was significantly shorter for the MMSE (14.75 ± 5.7 minutes) than for the NCSE (38.9 ± 12.9 minutes). The NCSE was found to be more sensitive than the MMSE in detecting cognitive impairment among geriatric inpatients, but its specificity and positive predictive values were lower. Beyond this pilot study, additional work examining the utility of the NCSE in other geriatric settings and for different purpose (e.g., as part of comprehensive assessment) needs to be performed.

Hyperactivity in Twins

A hypothesis was made that hyperactivity as stated by others was not a direct result of brain anoxia produced in pre and post-natal factors, but that they share a common genetic cause. A comparison between four Mz. and six Dz. sets of twins were made. It was found that all Mz. pairs were male and concordant to hyperactivity. In the Dz. group all pairs were discordant except one male-male combination. Also in the Dz. group hyperactivity was always present in the male partners but for one discordant pair where the syndrome was present in the female. The importance of genetics as a causative factor was not obviously due to the small amount of hyperactive females studied in this project.