Season of birth is not associated with risk of early adult death in rural Senegal.
BACKGROUND
In a rural area of the Gambia, West Africa, young adults born in the 'hungry' season had a high excess of deaths (mortality ratios (MR): 3.7 from 14.5 years and 10.3 from 25 years, P < 0.0001). Among several potential causal factors, fetal undernutrition was considered the most plausible. This study is a similar analysis of children and young adults living in rural Senegal, close to the Gambia.


METHODS
A cohort of 9192 subjects born 1962-2001 with prospectively collected dates of birth and death was analysed. MR by season of birth (July-December/January-June) was estimated using Cox's proportional hazards analysis. The nutritional status of non-pregnant women was analysed at monthly intervals 1990-1996.


RESULTS
MR by season of birth was slightly greater than 1 during infancy, and close to 1 from 1-5 years and from 5-14.5 years. From 14.5 years old the MR was 0.77 (95% CI: 0.47, 1.25, P = 0.29), compared with 0.53 (95% CI: 0.28, 1.02, P = 0.056) from 20 years and 0.33 (95% CI: 0.09, 1.25, P = 0.10) from 25 years. The weight of women varied strongly by season: means were 3.0-3.9 kg lower at the end of the rainy season (September-November) than during the dry season (February-May, P < 0.001 for each year).


CONCLUSIONS
This study found no increased risk of death among young adults born during the hungry season in a rural West African area despite large seasonal variations in women's nutritional status. The strongly increased risk in adult Gambians is probably not explained by fetal undernutrition.
Simondon
Kirsten B
KB
UR 24 (Epidemiology and Prevention Unit), Institut de Recherche pour le Développement (IRD, formerly named ORSTOM), BP 64501, 34394 Montpellier Cedex 5, France. kirsten.simondon@mpl.ird.fr
Elguero
Eric
E
Marra
Adama
A
Diallo
Aldiouma
A
Aaby
Peter
P
Simondon
François
F
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D001835:Body Weight; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D008297:Male; D009026:Mortality; D036801:Parturition; D011159:Population Surveillance / Q000379:methods; D011247:Pregnancy; D012307:Risk Factors; D012424:Rural Population; D012621:Seasons; D012675:Senegal / Q000453:epidemiology