Abstract
[S40.001] Variations in the Gender Ratio of Multiple Sclerosis Linked to Converging Smoking Trends in Men and Women
Natalia Palacios, Boston, MA, Alvaro Alonso, Minneapolis, MN, Henrik Bronnum-Hansen, Coppenhagen, Denmark, Alberto Ascherio, Boston, MA
OBJECTIVE: To examine if a time-dependent relationship exists between changing female-to male ratios of smoking and Multiple Sclerosis (MS) in worldwide birth cohorts from previously published studies. BACKGROUND: Smoking behavior in industrialized nations has changed dramatically over the second half of the 20th century, with diverging patterns in male and female smoking rates. During the same time period, an increase in the female to male ratio in MS incidence has been reported. We examined whether MS incidence in the two genders changed concomitantly with smoking, as would be expected if smoking truly increased MS risk. DESIGN/METHODS: We identified relevant studies reporting male and female age-specific incidence of MS throughout the world using within-country birth cohorts as units of observation. For each country and birth cohort, we then estimated the male to female ratio in MS incidence, and correlated these ratios with the corresponding male to female ratios in smoking behavior obtained from national statistics. In addition, in separate analyses we also examined in depth the within-country trends of smoking and MS for two populations in which statistics on MS are readily available: Canada and Denmark. RESULTS: We show that the gender ratio of MS is correlated with the gender ratio of smoking (r = 0.12, 95% CI: 0.02, 0.22; p = 0.02). This correlation supports an overall incidence rate ratio of 1.40 (95% CI: 1.02, 1.89) of MS for ever smokers as compared with never smokers. Furthermore, our within-country analyses of smoking and MS trends in Canada and Denmark show that, depending on model assumptions, smoking could explain 20 to 89% of the change in the female to male ratios of MS. CONCLUSIONS/RELEVANCE: Our results are consistent with the hypothesis that smoking increases the risk of MS. Smoking trends might partially explain changes in the MS gender ratio. Supported by: Dr. Ascherio: funding for studies of MS from NIH/NINDS. Natalia Palacios: Training Program in Environmental Epidemiology funded under grant no. T32 ES07069. The Danish Multiple Sclerosis Society finances the Danish Multiple Sclerosis Registry.
Category - MS and Related Diseases - Clinical Science
Wednesday, April 14, 2010 4:15 PM
Scientific Sessions: Multiple Sclerosis: Epidemiology (4:15 PM-5:30 PM)
Natalia Palacios, Boston, MA, Alvaro Alonso, Minneapolis, MN, Henrik Bronnum-Hansen, Coppenhagen, Denmark, Alberto Ascherio, Boston, MA
OBJECTIVE: To examine if a time-dependent relationship exists between changing female-to male ratios of smoking and Multiple Sclerosis (MS) in worldwide birth cohorts from previously published studies. BACKGROUND: Smoking behavior in industrialized nations has changed dramatically over the second half of the 20th century, with diverging patterns in male and female smoking rates. During the same time period, an increase in the female to male ratio in MS incidence has been reported. We examined whether MS incidence in the two genders changed concomitantly with smoking, as would be expected if smoking truly increased MS risk. DESIGN/METHODS: We identified relevant studies reporting male and female age-specific incidence of MS throughout the world using within-country birth cohorts as units of observation. For each country and birth cohort, we then estimated the male to female ratio in MS incidence, and correlated these ratios with the corresponding male to female ratios in smoking behavior obtained from national statistics. In addition, in separate analyses we also examined in depth the within-country trends of smoking and MS for two populations in which statistics on MS are readily available: Canada and Denmark. RESULTS: We show that the gender ratio of MS is correlated with the gender ratio of smoking (r = 0.12, 95% CI: 0.02, 0.22; p = 0.02). This correlation supports an overall incidence rate ratio of 1.40 (95% CI: 1.02, 1.89) of MS for ever smokers as compared with never smokers. Furthermore, our within-country analyses of smoking and MS trends in Canada and Denmark show that, depending on model assumptions, smoking could explain 20 to 89% of the change in the female to male ratios of MS. CONCLUSIONS/RELEVANCE: Our results are consistent with the hypothesis that smoking increases the risk of MS. Smoking trends might partially explain changes in the MS gender ratio. Supported by: Dr. Ascherio: funding for studies of MS from NIH/NINDS. Natalia Palacios: Training Program in Environmental Epidemiology funded under grant no. T32 ES07069. The Danish Multiple Sclerosis Society finances the Danish Multiple Sclerosis Registry.
Category - MS and Related Diseases - Clinical Science
Wednesday, April 14, 2010 4:15 PM
Scientific Sessions: Multiple Sclerosis: Epidemiology (4:15 PM-5:30 PM)
| Original language | English |
|---|---|
| Title of host publication | Abstracts |
| Publisher | American Academy of Neurology |
| Publication date | 2010 |
| Publication status | Published - 2010 |
| Event | 2010 AAN Annual Meeting - Toronto, Canada Duration: 10. Apr 2010 → 17. Apr 2010 |
Conference
| Conference | 2010 AAN Annual Meeting |
|---|---|
| Country/Territory | Canada |
| City | Toronto |
| Period | 10/04/2010 → 17/04/2010 |
Keywords
- Multiple Sclerosis
- Smoking
- epidemiology