Long-Term Follow-up of Asthma
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《新英格兰医药杂志》
To the Editor: The article by Sears et al. (Oct. 9 issue),1 as well as the accompanying editorial by Martinez,2 emphasizes the important contribution of early childhood experiences to the burden of asthma in adults in Dunedin, New Zealand, but fails to remark on the protective effect of breast-feeding on this disease. This omission appears to be a result of the method used to measure breast-feeding. According to an earlier report,3 the Dunedin study contains information on the duration of any breast-feeding, and more than half the women who initiated any breast-feeding (as compared with exclusive breast-feeding) weaned their infants by the time they were three months old. We ask the authors to provide any available data on breast-feeding.
Virginia R.G. Bachrach, M.D., M.P.H.
4179 Oak Hill Ave.
Palo Alto, CA 94306
virginia.bachrach@stanford.edu
Per Nafstad, M.D., Ph.D., M.P.H.
University of Oslo
0317 Oslo, Norway
Wendy Oddy, Ph.D.
Telethon Institute for Child Health Research
West Perth 6872, Australia
References
Sears MR, Greene JM, Willan AR, et al. A longitudinal, population-based, cohort study of childhood asthma followed to adulthood. N Engl J Med 2003;349:1414-1422.
Martinez FD. Toward asthma prevention: does all that really matters happen before we learn to read? N Engl J Med 2003;349:1473-1475.
Hood LJ, Faed JA, Silva PA, Buckfield PM. Breast feeding and some reasons for electing to wean the infant: a report from the Dunedin Multidisciplinary Child Development Study. N Z Med J 1978;88:273-276.
The authors reply: We found that breast-feeding did not have a protective effect on the development of atopy and asthma in this cohort. Rather, breast-feeding was associated with an increased risk of atopy and asthma.1 We verified that the accuracy of our breast-feeding data from records made prospectively in the first year of life was greater than 98 percent.2 Asthma developed at nine years of age in 12 percent of children who had been breast-fed for four weeks or longer, as compared with 6 percent of those not breast-fed (P=0.008). Thirty-six percent of those breast-fed for four weeks or longer, as compared with 24 percent of those not breast-fed, had mite sensitization (P=0.001), and 53 percent as compared with 37 percent, respectively, had positive skin tests (P<0.001).1
These findings were similar among children who were exclusively breast-fed; the rate of asthma was 10.7 percent among those breast-fed for four weeks or longer, as compared with 5.3 percent among those not breast-fed (P<0.01); the rate of atopy to mites, 33.9 percent versus 27.0 percent, respectively (P<0.05); and the rate of any atopy, 52.3 percent versus 39.6 percent, respectively (P<0.05).3 Prolonged breast-feeding (for six months or more) was associated with asthma in 10.9 percent of breast-fed children, as compared with 6.9 percent of non–breast-fed children.
Our findings are consistent with those of other studies that have examined long-term outcomes of breast-feeding.4,5 Differences among studies may be related primarily to the duration of follow-up, since protection has been seen in short-term studies, and an increased risk has been seen over the long term.
Malcolm R. Sears, M.B.
McMaster University
Hamilton, ON L8N 3Z5, Canada
searsm@mcmaster.ca
D. Robin Taylor, M.D.
Richie Poulton, Ph.D.
University of Otago
Dunedin, New Zealand
References
Sears MR, Greene JM, Willan AR, et al. Long-term relation between breastfeeding and development of atopy and asthma in children and young adults: a longitudinal study. Lancet 2002;360:901-907.
Sears MR, Taylor DR, Poulton R. Breastfeeding and asthma: appraising the controversy -- a rebuttal. Pediatr Pulmonol 2003;36:366-368.
Sears MR, Taylor DR, Greene JM, Poulton R, Herbison GP. Breastfeeding, atopy and asthma. Lancet 2003;361:175-176.
Rusconi F, Galassi C, Corbo GM, et al. Risk factors for early, persistent, and late-onset wheezing in young children. Am J Respir Crit Care Med 1999;160:1617-1622.
Wright AL, Holberg CJ, Taussig LM, Martinez FD. Factors influencing the relation of infant feeding to asthma and recurrent wheeze in childhood. Thorax 2001;56:192-197.
Virginia R.G. Bachrach, M.D., M.P.H.
4179 Oak Hill Ave.
Palo Alto, CA 94306
virginia.bachrach@stanford.edu
Per Nafstad, M.D., Ph.D., M.P.H.
University of Oslo
0317 Oslo, Norway
Wendy Oddy, Ph.D.
Telethon Institute for Child Health Research
West Perth 6872, Australia
References
Sears MR, Greene JM, Willan AR, et al. A longitudinal, population-based, cohort study of childhood asthma followed to adulthood. N Engl J Med 2003;349:1414-1422.
Martinez FD. Toward asthma prevention: does all that really matters happen before we learn to read? N Engl J Med 2003;349:1473-1475.
Hood LJ, Faed JA, Silva PA, Buckfield PM. Breast feeding and some reasons for electing to wean the infant: a report from the Dunedin Multidisciplinary Child Development Study. N Z Med J 1978;88:273-276.
The authors reply: We found that breast-feeding did not have a protective effect on the development of atopy and asthma in this cohort. Rather, breast-feeding was associated with an increased risk of atopy and asthma.1 We verified that the accuracy of our breast-feeding data from records made prospectively in the first year of life was greater than 98 percent.2 Asthma developed at nine years of age in 12 percent of children who had been breast-fed for four weeks or longer, as compared with 6 percent of those not breast-fed (P=0.008). Thirty-six percent of those breast-fed for four weeks or longer, as compared with 24 percent of those not breast-fed, had mite sensitization (P=0.001), and 53 percent as compared with 37 percent, respectively, had positive skin tests (P<0.001).1
These findings were similar among children who were exclusively breast-fed; the rate of asthma was 10.7 percent among those breast-fed for four weeks or longer, as compared with 5.3 percent among those not breast-fed (P<0.01); the rate of atopy to mites, 33.9 percent versus 27.0 percent, respectively (P<0.05); and the rate of any atopy, 52.3 percent versus 39.6 percent, respectively (P<0.05).3 Prolonged breast-feeding (for six months or more) was associated with asthma in 10.9 percent of breast-fed children, as compared with 6.9 percent of non–breast-fed children.
Our findings are consistent with those of other studies that have examined long-term outcomes of breast-feeding.4,5 Differences among studies may be related primarily to the duration of follow-up, since protection has been seen in short-term studies, and an increased risk has been seen over the long term.
Malcolm R. Sears, M.B.
McMaster University
Hamilton, ON L8N 3Z5, Canada
searsm@mcmaster.ca
D. Robin Taylor, M.D.
Richie Poulton, Ph.D.
University of Otago
Dunedin, New Zealand
References
Sears MR, Greene JM, Willan AR, et al. Long-term relation between breastfeeding and development of atopy and asthma in children and young adults: a longitudinal study. Lancet 2002;360:901-907.
Sears MR, Taylor DR, Poulton R. Breastfeeding and asthma: appraising the controversy -- a rebuttal. Pediatr Pulmonol 2003;36:366-368.
Sears MR, Taylor DR, Greene JM, Poulton R, Herbison GP. Breastfeeding, atopy and asthma. Lancet 2003;361:175-176.
Rusconi F, Galassi C, Corbo GM, et al. Risk factors for early, persistent, and late-onset wheezing in young children. Am J Respir Crit Care Med 1999;160:1617-1622.
Wright AL, Holberg CJ, Taussig LM, Martinez FD. Factors influencing the relation of infant feeding to asthma and recurrent wheeze in childhood. Thorax 2001;56:192-197.