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Smoking and acute appendicitis
CORRESPONDENCE
age 16 years and 48% reported that they first tried smoking by age 12 years. It is impossible to prove that smoking causes acute appendicitis, since we have insufficient data on the temporal relation of taking up smoking and acute appendicitis. However, this is the most plausible explanation for the relation: a high proportion of cohort members are likely to have started smoking before their appendicectomy and there is no evidence to suggest that the relation between smoking and appendicectomy is due to confounding. We do not suggest that smoking is the sole cause of acute appendicitis, but it does seem possible that, as for peptic ulcers, it is a cofactor that increases the risk of disease. *Scott M Montgomery, Roy E Pounder, Andrew J Wakefield Inflammatory Bowel Disease Study Group, Department of Medicine, Royal Free and University College Medical School, London NW3 2PF, UK (e-mail: [email protected]) 1
Montgomery SM, Pounder RE, Wakefield AJ. Smoking, passive smoking and acute appendicitis. Gut 1999; 44 (suppl 1): A74. 2 Barker DJP, Osmond C, Golding J, Wadsworth MEJ. Acute appendicitis and bathrooms in three samples of British children. BMJ 1988; 296: 956–58. 3 Kato I, Nomura AYM, Stemmermann GN, et al. A prospective study of gastric and duodenal ulcer and its relation to smoking, alcohol and diet. Am J Epidemiol 1992; 135: 521–30. 4 Sandler RS, Appendicectomy and ulcerative colitis. Lancet 1998; 352: 1797–98. 5 Addiss DG, Shaffer N, Fowler BS, Tauxe RV. The epidemiology of appendicitis and appendicectomy in the United States. Am J Epidemiol 1990; 132: 910–25.
Sir—Scott Montgomery and colleagues1 describe strong positive and independent associations of selfreported appendicectomy by age 26 years with active cigarette smoking in adult life and passive smoking in childhood. These findings, based on data from 5264 members of the 1970 British Cohort Study, seem invariant to adjustment for confounders. 1 The investigators suggest that smoking might increase the risk of acute inflammation of the appendix,1 although they did not investigate the time sequence of events, and, specifically, whether appendicectomy preceded or followed the start of active smoking. With data from the National Child Development Study, which aims to follow-up all British children born between March 3 and March 9, 1958,2 we investigated associations between active and passive smoking and the occurrence of appendicectomy in the periods birth to 11 years and 12–16
1712
Smoking variable
Number at risk
Adjusted odds ratio (95% CI)* 0-–11 years
12–16 years
0–16 years
1·00 0·66 (0·39–1·13) 0·76 (0·43–1·35)
1·00 1·04 (0·64–1·69) 1·11 (0·66–1·88)
1·00 0·84 (0·58–1·21) 0·93 (0·63–1·37)
Maternal smoking when child aged 16 years (cigarettes per day)† 0 3135 1·00 1–10‡ 1096 0·79 (0·50–1·26) >10 1331 1·28 (0·82–2·01)
1·00¶ 1·06 (0·65–1·74) 2·10 (1·33–3·33)
1·00II 0·89 (0·63–1·26) 1·63 (1·18–2·26)
Cohort member’s cigarette smoking at 16 and 23 years§ Never 2920 1·00 At 16 years not at 23 years 496 1·03 (0·60–1·76) At 23 years not at 16 years 736 1·02 (0·65–1·61) At 16 and 23 years 1410 0·92 (0·62–1·34)
1·00 0·88 (0·48–1·59) 0·62 (0·35–1·09) 0·81 (0·54–1·21)
1·00 0·95 (0·63–1·43) 0·82 (0·57–1·17) 0·86 (0·65–1·14)
Maternal smoking in pregnancy (cigarettes per day)† <1 4032 1–9 875 ⭓10 655
*Adjusted for potential confounding factors (sex, social class, overcrowding) and the other measures of passive and active smoking.†2 tests for trend across ungrouped smoking variables. ‡ Includes smokers smoking less than 1 cigarette per day. §2 tests for heterogeneity across smoking categories. IIp<0·05, test for trend. ¶p<0·01, test for trend.
Age-specific relative odds of appendicectomy by mother’s and child’s smoking
years. At age 11 years, parents were asked whether the child had had their appendix removed, and, if so, at what age this occurred; at age 16 years, parents were asked whether the study child had ever been admitted to hospital overnight, and if so, whether the child had had an appendicectomy and at what age. Information on sex and maternal smoking during pregnancy was obtained by midwives at birth, information on paternal social class, and overcrowding from parental report at age 11 years, and information on maternal smoking from parental report at age 16 years.2 Cohort members reported their own smoking habits at ages 16 and 23 years.2 We used logistic regression analysis in SAS version 6·0, on the basis of individuals with complete data, to investigate the relation between agespecific occurrence of appendicectomy and measures of active and passive smoke exposure with and without adjustment for each other, and for confounding by sex, social class, and overcrowding. Maternal smoking reported in 1974, when the cohort member was aged 16 years, was positively associated with the child’s lifetime risk of appendicectomy, independent of confounding factors and other measures of passive and active smoking (table). This association seemed to be due to a doubling in the odds of appendicectomy between 12 and 16 years, among children whose mothers smoked at least ten cigarettes per day (table). There was no evidence of any additional risk due to maternal smoking during pregnancy or the child’s own smoking habits (table). These data provide further evidence for an association between parental smoking and appendicectomy in later childhood and suggest that the association of active smoking with a history of appendicectomy1 is unlikely to be the result of selective uptake of
smoking by individuals whose appendix was removed in childhood. *Barbara K Butland, David P Strachan Department of Public Health Sciences, St George’s Hospital Medical School, London SW17 ORE, UK 1
Montgomery SM, Pounder RE, Wakefield AJ. Smoking in adults and passive smoking in children are associated with acute appendicitis. Lancet 1999; 353: 379. 2 City University Social Statistics Research Unit. National Child Development Study, 1958–[computer file]. Colchester: ESRC Data Archive, 1993.
Political cor rectness Sir—Mona Sfeir and Reuben Granich (March 27, p 1104)1 comment on the use of “Sir” in letters to The Lancet. What is wrong with the old traditional phase of “Sir”, even if there are more women than men on the editorial staff? It served well for many years without anybody believing that The Lancet is a sexist rag, and we do not think that any female editor can feel discriminated against by this more or less meaningless phrase. We wonder how letters should be addressed in the future, if “Sir” is not politically correct. Maybe with “Ladies and gentlemen” or “Human beings at the editorial staff” or “To whom it may concern”? We believe that The Lancet is a journal in which nobody is preferred or discriminated against because of sex, religion, or ethnic origin. There is no need to complain about the quota of women and minorities in The Lancet, because it has always been open to everyone who has something interesting to say, no matter who he or she is. We think this more important than the way letters are addressed. Monika Schindl, *Peter Birner Department of Gynaecology and Obstetrics, and *Clinical Institute of Clinical Pathology, University of Vienna, A-1090 Vienna, Austria 1
Sfeir M, Granich R. Affirmative action needed in The Lancet. Lancet 1999; 353: 1104.
THE LANCET • Vol 353 • May 15, 1999
age 16 years and 48% reported that they first tried smoking by age 12 years. It is impossible to prove that smoking causes acute appendicitis, since we have insufficient data on the temporal relation of taking up smoking and acute appendicitis. However, this is the most plausible explanation for the relation: a high proportion of cohort members are likely to have started smoking before their appendicectomy and there is no evidence to suggest that the relation between smoking and appendicectomy is due to confounding. We do not suggest that smoking is the sole cause of acute appendicitis, but it does seem possible that, as for peptic ulcers, it is a cofactor that increases the risk of disease. *Scott M Montgomery, Roy E Pounder, Andrew J Wakefield Inflammatory Bowel Disease Study Group, Department of Medicine, Royal Free and University College Medical School, London NW3 2PF, UK (e-mail: [email protected]) 1
Montgomery SM, Pounder RE, Wakefield AJ. Smoking, passive smoking and acute appendicitis. Gut 1999; 44 (suppl 1): A74. 2 Barker DJP, Osmond C, Golding J, Wadsworth MEJ. Acute appendicitis and bathrooms in three samples of British children. BMJ 1988; 296: 956–58. 3 Kato I, Nomura AYM, Stemmermann GN, et al. A prospective study of gastric and duodenal ulcer and its relation to smoking, alcohol and diet. Am J Epidemiol 1992; 135: 521–30. 4 Sandler RS, Appendicectomy and ulcerative colitis. Lancet 1998; 352: 1797–98. 5 Addiss DG, Shaffer N, Fowler BS, Tauxe RV. The epidemiology of appendicitis and appendicectomy in the United States. Am J Epidemiol 1990; 132: 910–25.
Sir—Scott Montgomery and colleagues1 describe strong positive and independent associations of selfreported appendicectomy by age 26 years with active cigarette smoking in adult life and passive smoking in childhood. These findings, based on data from 5264 members of the 1970 British Cohort Study, seem invariant to adjustment for confounders. 1 The investigators suggest that smoking might increase the risk of acute inflammation of the appendix,1 although they did not investigate the time sequence of events, and, specifically, whether appendicectomy preceded or followed the start of active smoking. With data from the National Child Development Study, which aims to follow-up all British children born between March 3 and March 9, 1958,2 we investigated associations between active and passive smoking and the occurrence of appendicectomy in the periods birth to 11 years and 12–16
1712
Smoking variable
Number at risk
Adjusted odds ratio (95% CI)* 0-–11 years
12–16 years
0–16 years
1·00 0·66 (0·39–1·13) 0·76 (0·43–1·35)
1·00 1·04 (0·64–1·69) 1·11 (0·66–1·88)
1·00 0·84 (0·58–1·21) 0·93 (0·63–1·37)
Maternal smoking when child aged 16 years (cigarettes per day)† 0 3135 1·00 1–10‡ 1096 0·79 (0·50–1·26) >10 1331 1·28 (0·82–2·01)
1·00¶ 1·06 (0·65–1·74) 2·10 (1·33–3·33)
1·00II 0·89 (0·63–1·26) 1·63 (1·18–2·26)
Cohort member’s cigarette smoking at 16 and 23 years§ Never 2920 1·00 At 16 years not at 23 years 496 1·03 (0·60–1·76) At 23 years not at 16 years 736 1·02 (0·65–1·61) At 16 and 23 years 1410 0·92 (0·62–1·34)
1·00 0·88 (0·48–1·59) 0·62 (0·35–1·09) 0·81 (0·54–1·21)
1·00 0·95 (0·63–1·43) 0·82 (0·57–1·17) 0·86 (0·65–1·14)
Maternal smoking in pregnancy (cigarettes per day)† <1 4032 1–9 875 ⭓10 655
*Adjusted for potential confounding factors (sex, social class, overcrowding) and the other measures of passive and active smoking.†2 tests for trend across ungrouped smoking variables. ‡ Includes smokers smoking less than 1 cigarette per day. §2 tests for heterogeneity across smoking categories. IIp<0·05, test for trend. ¶p<0·01, test for trend.
Age-specific relative odds of appendicectomy by mother’s and child’s smoking
years. At age 11 years, parents were asked whether the child had had their appendix removed, and, if so, at what age this occurred; at age 16 years, parents were asked whether the study child had ever been admitted to hospital overnight, and if so, whether the child had had an appendicectomy and at what age. Information on sex and maternal smoking during pregnancy was obtained by midwives at birth, information on paternal social class, and overcrowding from parental report at age 11 years, and information on maternal smoking from parental report at age 16 years.2 Cohort members reported their own smoking habits at ages 16 and 23 years.2 We used logistic regression analysis in SAS version 6·0, on the basis of individuals with complete data, to investigate the relation between agespecific occurrence of appendicectomy and measures of active and passive smoke exposure with and without adjustment for each other, and for confounding by sex, social class, and overcrowding. Maternal smoking reported in 1974, when the cohort member was aged 16 years, was positively associated with the child’s lifetime risk of appendicectomy, independent of confounding factors and other measures of passive and active smoking (table). This association seemed to be due to a doubling in the odds of appendicectomy between 12 and 16 years, among children whose mothers smoked at least ten cigarettes per day (table). There was no evidence of any additional risk due to maternal smoking during pregnancy or the child’s own smoking habits (table). These data provide further evidence for an association between parental smoking and appendicectomy in later childhood and suggest that the association of active smoking with a history of appendicectomy1 is unlikely to be the result of selective uptake of
smoking by individuals whose appendix was removed in childhood. *Barbara K Butland, David P Strachan Department of Public Health Sciences, St George’s Hospital Medical School, London SW17 ORE, UK 1
Montgomery SM, Pounder RE, Wakefield AJ. Smoking in adults and passive smoking in children are associated with acute appendicitis. Lancet 1999; 353: 379. 2 City University Social Statistics Research Unit. National Child Development Study, 1958–[computer file]. Colchester: ESRC Data Archive, 1993.
Political cor rectness Sir—Mona Sfeir and Reuben Granich (March 27, p 1104)1 comment on the use of “Sir” in letters to The Lancet. What is wrong with the old traditional phase of “Sir”, even if there are more women than men on the editorial staff? It served well for many years without anybody believing that The Lancet is a sexist rag, and we do not think that any female editor can feel discriminated against by this more or less meaningless phrase. We wonder how letters should be addressed in the future, if “Sir” is not politically correct. Maybe with “Ladies and gentlemen” or “Human beings at the editorial staff” or “To whom it may concern”? We believe that The Lancet is a journal in which nobody is preferred or discriminated against because of sex, religion, or ethnic origin. There is no need to complain about the quota of women and minorities in The Lancet, because it has always been open to everyone who has something interesting to say, no matter who he or she is. We think this more important than the way letters are addressed. Monika Schindl, *Peter Birner Department of Gynaecology and Obstetrics, and *Clinical Institute of Clinical Pathology, University of Vienna, A-1090 Vienna, Austria 1
Sfeir M, Granich R. Affirmative action needed in The Lancet. Lancet 1999; 353: 1104.
THE LANCET • Vol 353 • May 15, 1999