Document Detail

Declining sex ratios in Canada.
MedLine Citation:
PMID:  9006562     Owner:  NLM     Status:  MEDLINE    
OBJECTIVE: To examine the trends in the proportion of annual live births that were male in Canada and to compare the trends with those in the United States. DESIGN: Analysis of census data. SETTING: Canada as a whole and 4 main regions (West, Ontario, Quebec and Atlantic). SUBJECTS: All live births from 1930 to 1990. OUTCOME MEASURES: Sex ratio (expressed as the proportion of total live births that were male [male proportion]) overall and by region. RESULTS: The male proportion in Canada decreased significantly after 1970 (p < 0.001); this represented a cumulative loss of 2.2 male births per 1000 live births from 1970 to 1990. Although a decrease was observed in all four regions studied, only that in the Atlantic region was significant (p < 0.001), representing a cumulative loss of 5.6 male births per 1000 live births from 1970 to 1990. A significant decrease in the male proportion was also observed in the United States from 1970 to 1990 (p < 0.001), although to a lesser degree than that observed in Canada, and represented a cumulative loss of 1.0 male births per 1000 live births. CONCLUSIONS: The decreased sex ratio in Canada adds to the growing debate over changes in biological markers and their potential causes. In addition, the study illustrates the potential use of the sex ratio as a widely available, unambiguous measure of the reproductive health of large populations.
B B Allan; R Brant; J E Seidel; J F Jarrell
Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne     Volume:  156     ISSN:  0820-3946     ISO Abbreviation:  CMAJ     Publication Date:  1997 Jan 
Date Detail:
Created Date:  1997-03-10     Completed Date:  1997-03-10     Revised Date:  2008-11-20    
Medline Journal Info:
Nlm Unique ID:  9711805     Medline TA:  CMAJ     Country:  CANADA    
Other Details:
Languages:  eng     Pagination:  37-41     Citation Subset:  AIM; IM    
Department of Obstetrics and Gynecology, University of Calgary, Alta.
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MeSH Terms
Birth Rate*
Canada / epidemiology
Logistic Models
Sex Distribution
Sex Ratio*
United States / epidemiology
Comment In:
CMAJ. 1997 Jun 15;156(12):1695   [PMID:  9220915 ]
CMAJ. 1997 Jan 1;156(1):46-8   [PMID:  9006564 ]
Erratum In:
Can Med Assoc J 1997 Feb 1;156(3):348

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