Amyotrophic lateral sclerosis: gender differences in the use of mechanical ventilation.

BACKGROUND AND PURPOSE: Invasive and non-invasive mechanical ventilation are therapeutic options in patients with amyotrophic lateral sclerosis (ALS). Related to known national ALS incidence figures, the study aims to examine gender aspects versus physiological data in patients with ALS commencing mechanical ventilation. METHODS: ata from two nationwide registers involving all patients with ALS in Norway and Sweden who started invasive and non-invasive mechanical ventilation during 2002-2007. RESULTS: The total ALS population on invasive and non-invasive mechanical ventilation comprised n = 308 subjects [Norway n = 96 (72% men), Sweden n = 212 (69% men)]. Compared to Swedish ALS incidence figures, our finding of a male/female ratio of 2.3/1 in patients with ALS on invasive and non-invasive mechanical ventilation shows a statistically significant male predominance in the use of mechanical ventilation (P-value 0.0084 Chi square). Only 6.7% of men and 3.8% of women had invasive (via tracheotomy) ventilation (P = 0.344). Initiation of mechanical ventilation was acute (not planned) in 18% of patients (no gender difference). Age distribution (mean age 62), pulmonary function tests (FVC%pred, FEV(1) %pred), daytime blood gas analyses (PaO(2), PaCO(2)) and survival revealed no statistically significant gender differences. CONCLUSION: In Norwegian and Swedish patients with ALS on invasive and non-invasive mechanical ventilation, two-thirds were men. Associated with known national ALS male/female incidence figures, our finding shows that statistically significantly more men than women with ALS are using mechanical ventilation. Physiological data and survival were equal in both genders. This may indicate the need for a more aggressive approach to stimulate mechanical ventilation in female patients with ALS.

Interethnic difference in thiopurine methyltransferase activity.

A number of metabolic pathways are subject to both genetic polymorphism and interethnic differences. A catabolic pathway of 6-mercaptopurine, red blood cell (RBC) thiopurine methyltransferase (TPMT) activity showed genetic polymorphism in Caucasians, but variation according to ethnicity has not been studied. We investigated if red blood cell thiopurine methyltransferase was subject to interethnic variation in a Saami (Lappish; n = 36) and a Caucasian population (n = 50). The Saami population sample had 29% higher thiopurine methyltransferase activity, 17.0 +/- 3.3 U/ml red blood cell compared with the Caucasian population sample, 13.1 +/- 2.9 U/ml red blood cell (p much less than 0.001). Probit plots and frequency distribution histograms supported bimodality consistent with genetic polymorphism in both study populations. Differences in chronic diseases, drug consumption, age, or gender could not explain the interethnic difference in red blood cell thiopurine methyltransferase activity. The higher red blood cell thiopurine methyltransferase activity in the Saami population group indicates that these subjects may require higher dosages of thiopurine drugs than Caucasians.