Active and passive smoking and breast cancer in Japan: a pooled analysis of nine population-based cohort studies.
Int J Epidemiol
; 53(3)2024 Apr 11.
Article
em En
| MEDLINE
| ID: mdl-38604675
ABSTRACT
BACKGROUND:
Epidemiological studies have shown inconsistent results regarding the link between smoking and breast cancer risk, despite the biological plausibility of a positive association.METHODS:
Participants were 166â611 women from nine prospective cohort studies in Japan which launched in 1984-1994 and followed for 8-22 years. Information on smoking and secondhand smoke was obtained through self-administered baseline questionnaires. Breast cancer was defined as code C50 according to the International Classification of Diseases for Oncology, 3rd Edition or the International Classification of Diseases, 10th Revision. After adjusting for several potential confounders, relative risks for breast cancer were calculated in the individual studies according to the current or previous status of active and passive smoking using Cox regression, followed by a summary estimate of hazard ratios using random-effects meta-analyses.RESULTS:
Of the 60â441 participants who reported being premenopausal and 106â170 who reported being postmenopausal at baseline, 897 and 1168 developed breast cancer during follow-up, respectively. Compared with never smokers, current smokers had a higher risk of developing breast cancer before the age of 50 years. In addition, ever smokers who started smoking at 30 years of age or younger, or who started smoking before first childbirth, had a higher risk of developing breast cancer before the age of 50 years. No association between adulthood or childhood exposure to secondhand smoke and breast cancer was observed.CONCLUSION:
Smoking may increase the risk of premenopausal breast cancer, and smoking earlier in life might be especially harmful. The impact of secondhand smoke needs further investigation.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Contexto em Saúde:
13_ODS3_tobacco_control
Base de dados:
MEDLINE
Assunto principal:
Poluição por Fumaça de Tabaco
/
Neoplasias da Mama
Limite:
Female
/
Humans
País/Região como assunto:
Asia
Idioma:
En
Revista:
Int J Epidemiol
Ano de publicação:
2024
Tipo de documento:
Article