Letters to the Editor
nature publishing group
How Does Length of Stay in the United States Affect Colorectal Cancer Incidence Among Immigrant Asian Populations in California? Phani K. Molakatalla, MD, MPH1 and Anand R. Kumar, MD, MPH1 doi:10.1038/ajg.2014.248
To the Editor: Ladabaum et al. (1) described the variation in colorectal cancer (CRC) incidence rates among Asian subgroups in California, in relation to nativity, socioeconomic status (SES), and residence in ethnic enclave. Incidence was significantly different among the subgroups and was inversely associated with the level of “ethnic enclave” among Asians. The authors concluded that acquired environmental factors significantly affected CRC incidence. However, an important question remains unanswered. How long do Asian immigrants need to be exposed to these environmental factors before their CRC risk increases? In other words, how does the length of stay in the United States affect CRC incidence among Asian immigrants? The current study (1) attempts to dissect the genetic and environmental interactions in CRC causation. McMichael et al. (2) reported that immigrants who resided longer in Australia had CRC mortality rates approaching that of the native population. This change was more evident after residing in Australia for 16 years. Mexicans migrating as children to Los Angeles were noted by Mack et al. (3) to have higher incidence rates of CRC compared with adults. These studies were reported decades ago and did not factor in the increasing CRC incidence in the general population during those years. The duration of exposure to the environment could be a key factor in raising an individual’s CRC risk. In the current study (1), the authors seem to have the data on the age © 2014 by the American College of Gastroenterology
at which an Asian immigrant obtained the social security number. These data may be used as a surrogate measure for the number of years in the United States. Moreover, given the size of the study sample, relationship between the duration of stay in the United States and CRC risk among Asian immigrants can be established after adjusting for potential confounders. The current study (1) examines the influence of various environmental factors traditionally known to affect CRC incidence in a more structured manner. Can the authors provide more information on the duration of stay of Asian immigrants in the United States and its association with the risk for colorectal cancer?
Drs Molakatalla and Kumar (1) are correct that we have available data on the age at receipt of a social security number for persons diagnosed with colorectal cancer, and that this could serve as a lower bound estimate for time of immigration to the United States. These persons constitute the numerators in incidence calculations. Unfortunately, we do not have such data for the cohorts at risk—that is, the populations of immigrants that constitute the denominators. Without these, we are unable to calculate incidence rates adjusted for length of stay in the United States. We agree with Drs Molakatalla and Kumar (1) that analyses that can address this important question would be of great interest.
CONFLICT OF INTEREST
The authors declare no conflict of interest.
CONFLICT OF INTEREST The authors declare no conflict of interest.
REFERENCES
REFERENCES
1. Ladabaum U, Clarke CA, Press DJ et al. Colorectal cancer incidence in Asian populations in California: effect of nativity and neighborhood-level factors. Am J Gastroenterol 2014;109:579–88. 2. McMichael AJ, Giles G G. Cancer in migrants to Australia: extending the descriptive epidemiological data. Cancer Res 1988;48:751–6. 3. Mack TM, Walker A, Mack W et al. Cancer in hispanics in Los Angeles county. Natl Cancer Inst Monogr 1985;69:99–104.
1. Molakatalla PK, Kumar AR. How does length of stay in the United States affect colorectal cancer incidence among immigrant Asian populations in California? Am J Gastroentrol 2014;109:1687 (this issue).
1
Einstein Medical Center, Department of Gastroenterology, Philadelphia, Pennsylvania, USA. Correspondence: Phani K. Molakatalla, MD, MPH, Einstein Medical Center, Department of Gastroenterology, 5401 Old york Road, Klein, Suite 363, Philadelphia, Pennsylvania 19141, USA. E-mail: [email protected]
Response to Molakatalla and Kumar 1, 2
Uri Ladabaum, MD, MS , Christina A. Clarke, PhD1,2, Iona Cheng, PhD1, 2 and Scarlett Lin Gomez, PhD1, 2
1
Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, California, USA; 2Cancer Prevention Institute of California, Fremont, California, USA. Correspondence: Uri Ladabaum, MD, MS, Division of Gastroenterology and Hepatology, Stanford University School of Medicine, 450 Broadway St, Pavillion C 4th Floor, MC: 6341, Redwood city, California 94063, USA. E-mail: [email protected]
Comment on Parikh et al. Ross A. Sage, MD1, Estela Mogrovejo, MD1, Atulkumar Patel, MD1 and Palaniappan Manickam, MD1 doi:10.1038/ajg.2014.252
doi:10.1038/ajg.2014.259
To the Editor: Drs Molakatalla and Kumar (1) raise an important point. It is reasonable to hypothesize that the risk of colorectal cancer in immigrants is associated with the length of stay in the United States.
To the Editor: We read with great interest the article by Parikh et al. (1). The authors performed a retrospective review comparing patients having an ERCP on a weekend or delaying it until Monday and found a significant difference in the length of stay The American Journal of GASTROENTEROLOGY
1687
nature publishing group
How Does Length of Stay in the United States Affect Colorectal Cancer Incidence Among Immigrant Asian Populations in California? Phani K. Molakatalla, MD, MPH1 and Anand R. Kumar, MD, MPH1 doi:10.1038/ajg.2014.248
To the Editor: Ladabaum et al. (1) described the variation in colorectal cancer (CRC) incidence rates among Asian subgroups in California, in relation to nativity, socioeconomic status (SES), and residence in ethnic enclave. Incidence was significantly different among the subgroups and was inversely associated with the level of “ethnic enclave” among Asians. The authors concluded that acquired environmental factors significantly affected CRC incidence. However, an important question remains unanswered. How long do Asian immigrants need to be exposed to these environmental factors before their CRC risk increases? In other words, how does the length of stay in the United States affect CRC incidence among Asian immigrants? The current study (1) attempts to dissect the genetic and environmental interactions in CRC causation. McMichael et al. (2) reported that immigrants who resided longer in Australia had CRC mortality rates approaching that of the native population. This change was more evident after residing in Australia for 16 years. Mexicans migrating as children to Los Angeles were noted by Mack et al. (3) to have higher incidence rates of CRC compared with adults. These studies were reported decades ago and did not factor in the increasing CRC incidence in the general population during those years. The duration of exposure to the environment could be a key factor in raising an individual’s CRC risk. In the current study (1), the authors seem to have the data on the age © 2014 by the American College of Gastroenterology
at which an Asian immigrant obtained the social security number. These data may be used as a surrogate measure for the number of years in the United States. Moreover, given the size of the study sample, relationship between the duration of stay in the United States and CRC risk among Asian immigrants can be established after adjusting for potential confounders. The current study (1) examines the influence of various environmental factors traditionally known to affect CRC incidence in a more structured manner. Can the authors provide more information on the duration of stay of Asian immigrants in the United States and its association with the risk for colorectal cancer?
Drs Molakatalla and Kumar (1) are correct that we have available data on the age at receipt of a social security number for persons diagnosed with colorectal cancer, and that this could serve as a lower bound estimate for time of immigration to the United States. These persons constitute the numerators in incidence calculations. Unfortunately, we do not have such data for the cohorts at risk—that is, the populations of immigrants that constitute the denominators. Without these, we are unable to calculate incidence rates adjusted for length of stay in the United States. We agree with Drs Molakatalla and Kumar (1) that analyses that can address this important question would be of great interest.
CONFLICT OF INTEREST
The authors declare no conflict of interest.
CONFLICT OF INTEREST The authors declare no conflict of interest.
REFERENCES
REFERENCES
1. Ladabaum U, Clarke CA, Press DJ et al. Colorectal cancer incidence in Asian populations in California: effect of nativity and neighborhood-level factors. Am J Gastroenterol 2014;109:579–88. 2. McMichael AJ, Giles G G. Cancer in migrants to Australia: extending the descriptive epidemiological data. Cancer Res 1988;48:751–6. 3. Mack TM, Walker A, Mack W et al. Cancer in hispanics in Los Angeles county. Natl Cancer Inst Monogr 1985;69:99–104.
1. Molakatalla PK, Kumar AR. How does length of stay in the United States affect colorectal cancer incidence among immigrant Asian populations in California? Am J Gastroentrol 2014;109:1687 (this issue).
1
Einstein Medical Center, Department of Gastroenterology, Philadelphia, Pennsylvania, USA. Correspondence: Phani K. Molakatalla, MD, MPH, Einstein Medical Center, Department of Gastroenterology, 5401 Old york Road, Klein, Suite 363, Philadelphia, Pennsylvania 19141, USA. E-mail: [email protected]
Response to Molakatalla and Kumar 1, 2
Uri Ladabaum, MD, MS , Christina A. Clarke, PhD1,2, Iona Cheng, PhD1, 2 and Scarlett Lin Gomez, PhD1, 2
1
Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, California, USA; 2Cancer Prevention Institute of California, Fremont, California, USA. Correspondence: Uri Ladabaum, MD, MS, Division of Gastroenterology and Hepatology, Stanford University School of Medicine, 450 Broadway St, Pavillion C 4th Floor, MC: 6341, Redwood city, California 94063, USA. E-mail: [email protected]
Comment on Parikh et al. Ross A. Sage, MD1, Estela Mogrovejo, MD1, Atulkumar Patel, MD1 and Palaniappan Manickam, MD1 doi:10.1038/ajg.2014.252
doi:10.1038/ajg.2014.259
To the Editor: Drs Molakatalla and Kumar (1) raise an important point. It is reasonable to hypothesize that the risk of colorectal cancer in immigrants is associated with the length of stay in the United States.
To the Editor: We read with great interest the article by Parikh et al. (1). The authors performed a retrospective review comparing patients having an ERCP on a weekend or delaying it until Monday and found a significant difference in the length of stay The American Journal of GASTROENTEROLOGY
1687
