Sex ratio of multiple sclerosis in persons born from 1930 to 1979 and its relation to latitude in Norway.

A remarkable increase in female to male ratio of multiple sclerosis (MS) is recognised in high incidence areas. Norway is a high-risk area for MS, spanning latitudes 58-71 °N. We studied whether the sex ratio has changed over time and whether it differs by clinical phenotype or by latitude. Population-based epidemiological data and data from the Norwegian MS Registry on patients born from 1930 to 1979 were combined in this study. Place of birth was retrieved from the Norwegian Population Registry and information on clinical subtypes was obtained from the Norwegian MS Registry. The female to male ratio ranged from 1.7 to 2.7 (median 2.0) in 5,469 patients born in Norway, and increased slightly by 5-year blocks of year of birth (p = 0.043). The sex ratio was 2.6:1 in 825 patients born 1970-1979, which is significantly higher than in those born 1930-1969 (p < 0.001). In patients with relapsing remitting onset, the sex ratio was 2.4:1, while it was 1.1:1 in those with primary progressive disease. The sex ratio did not differ between the south, the middle and the north of the country. The overall sex ratio of MS is strongly determined by cases with relapsing remitting onset. We did not observe the remarkable increase in sex ratios of MS reported from other high-risk areas. The high sex ratio in the youngest birth cohorts may change as an increasing proportion of cases in this age group is being diagnosed. Sex ratio was not associated with latitude.

Month of birth as a latitude-dependent risk factor for multiple sclerosis in Norway.

OBJECTIVE: We aimed to determine if the risk of Multiple Sclerosis (MS) is associated with month of birth in Norway and to explore a possible latitudinal gradient. METHODS: All patients with MS born between 1930 and 1979 registered in the Norwegian MS Registry or ascertained in Norwegian prevalence studies were included (n = 6649). The latitude gradient was divided in Southern, Middle and Northern Norway, according to the estimated regional yearly mean vitamin D effective UV dose. RESULTS: Risk of MS was 11% higher for those born in April (p = 0.045), and 5% higher for those born in May (p = 0.229), 5% lower for those born in November (p = 0.302) and 12% lower for those born in February (p = 0.053) compared with the corresponding population, unaffected mothers and siblings. In Southern Norway the odds ratio of MS births in April and May was 1.05 (0.98-1.24), in Middle Norway 1.11 (0.97-1.27) and in Northern Norway 1.28 (1.0-1.63) compared with the other months. CONCLUSIONS: This study confirms previous reports of increased MS births in spring and decreased MS births in the winter months. This could support the role of decreased sunlight exposure during pregnancy and vitamin D deficiency in prenatal life in MS.

Anxiety and depression in multiple sclerosis. A comparative population-based study in Nord-Trøndelag County, Norway.

Anxiety and depression are widely distributed symptoms among multiple sclerosis patients and in the general population. We assessed the prevalence of anxiety and depression in the multiple sclerosis population in Nord-Trøndelag County, Norway compared with Norway's general population. The Hospital Anxiety and Depression Scale questionnaire was completed by 172 MS patients and 56,000 controls. A cut-off of > or =8 was used to define significant symptoms of anxiety and depression. Fatigue was measured using Krupp's Fatigue Severity Scale, with a mean cut-off of >4. Among men, 31.1% of the multiple sclerosis patients reported anxiety, while only 12.1% of the control population reported this symptom (p = 0.002). For women, the prevalence of anxiety was 29.7% versus 17.4% (p < 0.001). Depression was reported by 26.2% of the men with multiple sclerosis compared with 10.8% of the controls (p < 0.001). The corresponding figures for women were 25.2% versus 10.4% (p < 0.001). Anxiety and depression were not correlated with duration of disease or disability measured by the Expanded Disability Status Scale. Among women, fatigue was associated with anxiety (p < or = 0.010) and depression (p = 0.007). No such association was found among men. Anxiety and depression occur more frequently in multiple sclerosis patients than in the general population. Fatigue was associated with these neuropsychiatric manifestations in only women.

Trace elements in serum from patients with Parkinson's disease--a prospective case-control study: the Nord-Trøndelag Health Study (HUNT).

To assess whether trace elements are involved in Parkinson's disease (PD) we have conducted a prospective study where 19 trace elements have been determined in serum collected from 33 patients before they were diagnosed with the disease, and 99 controls. As a follow-up, serum from 19 of the same patients collected 4-12 years after they were diagnosed with PD has been analysed. In the prospective part of the study, the only significant difference was a slightly lower content of Hg in the patient group than in the controls. In the follow-up, significantly higher levels of Hg, Ni, and Y, and lower levels of Ca, Fe, Mg, Mn, Rb and Se were found in the serum samples collected after the patients were diagnosed with PD compared with pre-diagnostic levels.