This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Yasui, Y. Articles by Potter, J. D. Search for Related Content PubMed Articles by Yasui, Y. Articles by Potter, J. D.

Reply

Cancer Prevention Research Program, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109-1024

We thank Dr. Glaser for her thoughtful comments on our article (1) . She raised three issues, and we take this opportunity to respond to them.

In the first paragraph of her letter, Dr. Glaser stated, "Young adult Asians have been shown to have low HD¹ rates not only in Asia but also in the United States, despite their socioeconomic conditions being more likely to favor delayed primary EBV infection. Thus, the assumption of Yasui et al. is questionable ..." We are puzzled by this comment for two reasons. First, Asian Americans are socioeconomically diverse and do not necessarily have socioeconomic conditions that are "more likely to favor delayed primary EBV infection" (2) . Second, our reasoning was questioned on the basis of Dr. Glaser’s speculation that Asian populations in high socioeconomic conditions should have a tendency for delayed primary EBV infection. However, this hypothesis is refuted by the recent data that the majority of Japanese children are seropositive for EBV within the first few years of life and that IM is a disease of early childhood in Japan (3) , in spite of the fact that the country’s economic conditions may favor delayed primary EBV infection. Note that what has been shown in the literature is a low HD rate among young adult Asians, not the tendency for Asians to have delayed primary EBV infection. It is entirely possible that Asians, regardless of their socioeconomic status, may share some factors that render them more likely to EBV infection early in life. See also the "Discussion" in our article (1) for related comments on the difficulty of explaining the observed associations by socioeconomic conditions (1) .

In the second paragraph of her letter, Dr. Glaser pointed out the extremely low prevalence of IM in older women, both in our study and in a California survey, and stated that they were "unlikely to have had delayed EBV infection." We believe that the low prevalence of diagnosed IM among older women is explained by under-diagnosis of IM in earlier years in the United States and does not imply that their likelihood of having had delayed EBV infection is low. The following data support our interpretation: IM diagnosis in the state of Connecticut increased from 3.9 cases per 100,000 in 1948 to 46.7 cases per 100,000 in 1967 (4) , more than a 10-fold increase in 20 years, illustrating the under-diagnosis of IM in earlier years in the United States. For a similar 20-year period between 1950 and 1969 in Rochester, Minnesota, however, a carefully conducted study by a Mayo Clinic team reported no increase in the incidence of IM (5) . These findings suggest that the low prevalence of diagnosed IM in older women merely reflects the era in which IM was significantly under-diagnosed.

Finally, our data were consistent with the Danish IM follow-up study cited by Dr. Glaser in that our data did not show an overall association between IM history and breast cancer risk. Our data showed a strong association between age at IM onset and breast cancer risk. Note that the great majority of women without IM history have presumably had an EBV infection at varying ages. Thus, it is unsurprising to observe no overall association between IM history and breast cancer risk, even when there is a strong association between age at EBV infection and breast cancer risk.

Although our viewpoints regarding the above issues differ from Dr. Glaser’s, we strongly agree with her that additional studies are needed to confirm or refute the proposed hypothesis.

Footnotes

The abbreviations used are: HD, Hodgkin’s disease; IM, infectious mononucleosis.

Received 10/18/02; accepted 11/ 5/02.

References

1. Yasui Y., Potter J. D., Stanford J. L., Rossing M. A., Winget M. D., Bronner M., Daling J. Breast cancer risk and "delayed" primary Epstein-Barr virus infection. Cancer Epidemiol. Biomark. Prev., 10: 9-16, 2001.[Abstract/Free Full Text]
2. U.S. Department of Commerce, Economics and Statistics Administration, Bureau of the Census. . We, the American Asians, Washington DC 1993.
3. Kanegane H., Kanegane C., Yachie A., Miyawaki T., Tosato G. Infectious mononucleosis as a disease of early childhood in Japan caused by primary Epstein-Barr virus infection. Acta Paediatr. Jpn., 39: 166-171, 1997.[Medline]
4. Christine B. W. Infectious mononucleosis. Conn. Health Bull., 82: 115-119, 1968.
5. Henke C. E., Kurland L. T., Elveback L. R. Infectious mononucleosis in Rochester, Minnesota, 1950 through 1969. Am. J. Epidemiol., 98: 483-490, 1973.[Abstract/Free Full Text]

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Yasui, Y. Articles by Potter, J. D. Search for Related Content PubMed Articles by Yasui, Y. Articles by Potter, J. D.