Time From Smoking Cessation and Inflammatory Markers: New Evidence From a Cross-Sectional Analysis of ELSA-Brasil.
BACKGROUND
The time for inflammatory markers of former smokers to revert to never smoker levels is still controversial, ranging from 5 to 20 years. We aimed to determine the time from smoking cessation for white blood cell (WBC) count and serum C-reactive protein (CRP) levels to return to those of never-smokers, after adjusting for confounding factors and for secondhand smoke (SHS) exposure among participants of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).


METHODS
Cross-sectional analysis of baseline participants of ELSA-Brasil. We used linear regression analysis and generalized linear models with gamma distribution and logarithmic link function to estimate the association of WBC count and CRP levels with time from smoking cessation. The following confounding factors were considered: sex, age, education, SHS, alcohol consumption, leisure-time physical activity, BMI, total cholesterol/HDL ratio, hypertension, diabetes, cardiovascular disease, and chronic obstructive pulmonary disease (COPD). Results: After all adjustments, time from smoking cessation <10 years remained associated with higher WBC count (eg, time from smoking cessation ≥ 5 and <10 years: β: 167.92; 95%CI: 23.52 312.31), while only time from smoking cessation <1 year remained associated with higher arithmetic mean of CRP (AMR: 1.26, 95%CI: 1.03‒1.54).


CONCLUSIONS
Levels of inflammatory markers were similar to those of never-smokers 1 year after smoking cessation for CRP and 10 years after for WBC.


CONCLUSIONS
The results may add to the arsenal health professionals have to encourage their patients to quit smoking, as some harms from smoking appear to revert to never-smokers' level sooner than previously reported. Longitudinal studies should confirm our findings.
Postgraduate Program in Public Health and Hospital das Clínicas, Faculty of Medicine, Universidade Federal de Minas Gerais, Minas Gerais, Brazil.
Flávia Soares
FS
Peres
Postgraduate Program in Public Health and Hospital das Clínicas, Faculty of Medicine, Universidade Federal de Minas Gerais, Minas Gerais, Brazil.
Sandhi Maria
SM
Barreto
Postgraduate Program in Public Health and Hospital das Clínicas, Faculty of Medicine, Universidade Federal de Minas Gerais, Minas Gerais, Brazil.
Lidyane V
LV
Camelo
Postgraduate Program in Public Health and Hospital das Clínicas, Faculty of Medicine, Universidade Federal de Minas Gerais, Minas Gerais, Brazil.|Postgraduate Program in Infectious Diseases and Tropical Medicine and Hospital das Clínicas, Faculty of Medicine, Universidade Federal de Minas Gerais, Minas Gerais, Brazil.
Antonio Luiz P
ALP
Ribeiro
Postgraduate Program in Pathology and Laboratory Medicine, Faculty of Medicine, Universidade Federal de Minas Gerais, Minas Gerais, Brazil.
Pedro Guatimosim
PG
Vidigal
Postgraduate Program in Epidemiology and Hospital de Clinicas de Porto Alegre, Faculty of Medicine, Universidade Federal do Rio Grande do Sul, Rio Grande do Sul, Brazil.
Bruce Bartholow
BB
Duncan
Postgraduate Program in Public Health and Hospital das Clínicas, Faculty of Medicine, Universidade Federal de Minas Gerais, Minas Gerais, Brazil.
Luana
L
Giatti
D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood*; D001938:Brazil / Q000453:epidemiology; D002097:C-Reactive Protein / Q000378:metabolism*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007958:Leukocyte Count; D016014:Linear Models; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D012907:Smoking / Q000009:adverse effects / Q000097:blood / Q000453:epidemiology*; D016540:Smoking Cessation; D013997:Time Factors
D015415:Biomarkers; D002097:C-Reactive Protein