Incidence of chronic persistent rheumatoid arthritis and the impact of smoking: A Historical Twin Cohort Study

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Abstract

Objective: To assess the incidence of chronic persistent rheumatoid arthritis (RA) in a population-based cohort of twins and to determine the impact of smoking. Methods: In a historical cohort study on twins born in 1920 to 1982, we identified 157 cases of RA among 45,280 responders (response rate 80%). Information on smoking was obtained by questionnaire and interview. A mixed-effects Poisson regression model was used to estimate incidence rate ratios with age, sex, smoking duration, and smoking intensity as covariates. We used the SplitLexis procedure in the Epi R package to study a possible effect of period or cohort in addition to age on the variation of the incidence. Results: The annual incidence of chronic persistent RA was 18.8 per 100,000 person-years, ages 15–73 years (females 25.2, males 12.0), increasing with age to a maximum at age 60 years in females and age 70 years in males. The incidence rate ratio among ever-smoking patients was 1.96 (95% confidence interval [95% CI] 1.43–3.76), 1.93 (95% CI 1.00–3.7) after 30 pack-years, and 1.034 (P < 0.001) per year of smoking, implying a doubling of risk after 20 years regardless of sex and smoking intensity. We did not detect significant period or cohort effects. Conclusion: The incidence of chronic persistent RA is lower than the incidence figures reported in inception cohorts. Smoking duration, but not intensity, doubled the risk of RA after 20 years of smoking in both sexes.

Original languageEnglish
JournalArthritis Care & Research
Volume69
Issue number5
Pages (from-to)616–624
ISSN2151-464X
DOIs
Publication statusPublished - May 2017

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Twin Studies
Cohort Studies
Smoking
Incidence
Confidence Intervals
Cohort Effect
Interviews

Keywords

  • Adolescent
  • Adult
  • Aged
  • Arthritis, Rheumatoid/epidemiology
  • Cohort Studies
  • Diseases in Twins/epidemiology
  • Female
  • Humans
  • Incidence
  • Male
  • Middle Aged
  • Risk Factors
  • Smoking/adverse effects
  • Time Factors
  • Young Adult

Cite this

@article{5483fdc8f07440f9a66af0b27f453a85,
title = "Incidence of chronic persistent rheumatoid arthritis and the impact of smoking: A Historical Twin Cohort Study",
abstract = "Objective: To assess the incidence of chronic persistent rheumatoid arthritis (RA) in a population-based cohort of twins and to determine the impact of smoking. Methods: In a historical cohort study on twins born in 1920 to 1982, we identified 157 cases of RA among 45,280 responders (response rate 80{\%}). Information on smoking was obtained by questionnaire and interview. A mixed-effects Poisson regression model was used to estimate incidence rate ratios with age, sex, smoking duration, and smoking intensity as covariates. We used the SplitLexis procedure in the Epi R package to study a possible effect of period or cohort in addition to age on the variation of the incidence. Results: The annual incidence of chronic persistent RA was 18.8 per 100,000 person-years, ages 15–73 years (females 25.2, males 12.0), increasing with age to a maximum at age 60 years in females and age 70 years in males. The incidence rate ratio among ever-smoking patients was 1.96 (95{\%} confidence interval [95{\%} CI] 1.43–3.76), 1.93 (95{\%} CI 1.00–3.7) after 30 pack-years, and 1.034 (P < 0.001) per year of smoking, implying a doubling of risk after 20 years regardless of sex and smoking intensity. We did not detect significant period or cohort effects. Conclusion: The incidence of chronic persistent RA is lower than the incidence figures reported in inception cohorts. Smoking duration, but not intensity, doubled the risk of RA after 20 years of smoking in both sexes.",
keywords = "Cohort studies, Incidence, Rheumatoid arthritis, Smoking, Twins, Adolescent, Adult, Aged, Arthritis, Rheumatoid/epidemiology, Cohort Studies, Diseases in Twins/epidemiology, Female, Humans, Incidence, Male, Middle Aged, Risk Factors, Smoking/adverse effects, Time Factors, Young Adult",
author = "Svendsen, {Anders J} and Peter Junker and Gunnar Houen and Kyvik, {Kirsten O} and Christian Nielsen and Axel Skytthe and Ren{\'e} Holst",
note = "{\circledC} 2016, American College of Rheumatology.",
year = "2017",
month = "5",
doi = "10.1002/acr.22987",
language = "English",
volume = "69",
pages = "616–624",
journal = "Arthritis Care & Research",
issn = "2151-464X",
publisher = "JohnWiley & Sons, Inc.",
number = "5",

}

TY - JOUR

T1 - Incidence of chronic persistent rheumatoid arthritis and the impact of smoking

T2 - A Historical Twin Cohort Study

AU - Svendsen, Anders J

AU - Junker, Peter

AU - Houen, Gunnar

AU - Kyvik, Kirsten O

AU - Nielsen, Christian

AU - Skytthe, Axel

AU - Holst, René

N1 - © 2016, American College of Rheumatology.

PY - 2017/5

Y1 - 2017/5

N2 - Objective: To assess the incidence of chronic persistent rheumatoid arthritis (RA) in a population-based cohort of twins and to determine the impact of smoking. Methods: In a historical cohort study on twins born in 1920 to 1982, we identified 157 cases of RA among 45,280 responders (response rate 80%). Information on smoking was obtained by questionnaire and interview. A mixed-effects Poisson regression model was used to estimate incidence rate ratios with age, sex, smoking duration, and smoking intensity as covariates. We used the SplitLexis procedure in the Epi R package to study a possible effect of period or cohort in addition to age on the variation of the incidence. Results: The annual incidence of chronic persistent RA was 18.8 per 100,000 person-years, ages 15–73 years (females 25.2, males 12.0), increasing with age to a maximum at age 60 years in females and age 70 years in males. The incidence rate ratio among ever-smoking patients was 1.96 (95% confidence interval [95% CI] 1.43–3.76), 1.93 (95% CI 1.00–3.7) after 30 pack-years, and 1.034 (P < 0.001) per year of smoking, implying a doubling of risk after 20 years regardless of sex and smoking intensity. We did not detect significant period or cohort effects. Conclusion: The incidence of chronic persistent RA is lower than the incidence figures reported in inception cohorts. Smoking duration, but not intensity, doubled the risk of RA after 20 years of smoking in both sexes.

AB - Objective: To assess the incidence of chronic persistent rheumatoid arthritis (RA) in a population-based cohort of twins and to determine the impact of smoking. Methods: In a historical cohort study on twins born in 1920 to 1982, we identified 157 cases of RA among 45,280 responders (response rate 80%). Information on smoking was obtained by questionnaire and interview. A mixed-effects Poisson regression model was used to estimate incidence rate ratios with age, sex, smoking duration, and smoking intensity as covariates. We used the SplitLexis procedure in the Epi R package to study a possible effect of period or cohort in addition to age on the variation of the incidence. Results: The annual incidence of chronic persistent RA was 18.8 per 100,000 person-years, ages 15–73 years (females 25.2, males 12.0), increasing with age to a maximum at age 60 years in females and age 70 years in males. The incidence rate ratio among ever-smoking patients was 1.96 (95% confidence interval [95% CI] 1.43–3.76), 1.93 (95% CI 1.00–3.7) after 30 pack-years, and 1.034 (P < 0.001) per year of smoking, implying a doubling of risk after 20 years regardless of sex and smoking intensity. We did not detect significant period or cohort effects. Conclusion: The incidence of chronic persistent RA is lower than the incidence figures reported in inception cohorts. Smoking duration, but not intensity, doubled the risk of RA after 20 years of smoking in both sexes.

KW - Cohort studies

KW - Incidence

KW - Rheumatoid arthritis

KW - Smoking

KW - Twins

KW - Adolescent

KW - Adult

KW - Aged

KW - Arthritis, Rheumatoid/epidemiology

KW - Cohort Studies

KW - Diseases in Twins/epidemiology

KW - Female

KW - Humans

KW - Incidence

KW - Male

KW - Middle Aged

KW - Risk Factors

KW - Smoking/adverse effects

KW - Time Factors

KW - Young Adult

U2 - 10.1002/acr.22987

DO - 10.1002/acr.22987

M3 - Journal article

C2 - 27390149

VL - 69

SP - 616

EP - 624

JO - Arthritis Care & Research

JF - Arthritis Care & Research

SN - 2151-464X

IS - 5

ER -