Limits...
Ethnic differences in the time trend of female breast cancer incidence: Singapore, 1968-2002.

Sim X, Ali RA, Wedren S, Goh DL, Tan CS, Reilly M, Hall P, Chia KS - BMC Cancer (2006)

Bottom Line: While our analyses provided some evidence that an age-drift model described the trend seen in the Indians, age-period-cohort model and age-cohort model had the best fit for the Chinese and Malays aged 25 to 79 respectively.The observed dissimilarity among ethnic groups suggests ethnic differences in exposure or response to certain risk factors.It is likely that longer and subtler differences in childbearing trends and other risk factors may further explain these ethnic differences.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centre for Molecular Epidemiology, National University of Singapore and Genome Institute of Singapore, Singapore. cmesx@nus.edu.sg <cmesx@nus.edu.sg>

ABSTRACT

Background: From 1968 to 2002, Singapore experienced an almost three-fold increase in breast cancer incidence. This increase appeared to be different across the three main ethnic groups: Chinese, Malays and Indians. This paper used age-period-cohort (APC) modelling, to determine the effects of age at diagnosis, calendar period, and birth cohort on breast cancer incidence for each ethnic group.

Methods: This study included all breast cancer cases (n = 15,269) in the three ethnic groups, reported to the Singapore Cancer Registry from 1968 to 2002 between the ages 25 to 79. Age-specific fertility rates from the Department of Statistics were used to explore the role of fertility.

Results: In the 1970s, Indian women had the highest age-standardized breast cancer but by the mid-1980s the highest rates were seen among the Chinese. Remarkable differences were seen in the age-specific incidence rates by ethnic groups. After age 49, the incidence rates for the Chinese and Malays leveled off whereas it continued to rise in the Indians. While our analyses provided some evidence that an age-drift model described the trend seen in the Indians, age-period-cohort model and age-cohort model had the best fit for the Chinese and Malays aged 25 to 79 respectively. Overall, Chinese and Malay women born in later cohorts were at increased risk of developing breast cancer relative to their counterparts in the earlier cohorts. The three ethnic groups experienced similar changes in their fertility in the 1970s, which likely explained much of the increase in their breast cancer incidence but not the ethnic differences. There was a stronger inverse association between total fertility rate and pre-menopausal breast cancer incidence in the Chinese and Malays than the Indians.

Conclusion: The observed dissimilarity among ethnic groups suggests ethnic differences in exposure or response to certain risk factors. It is likely that longer and subtler differences in childbearing trends and other risk factors may further explain these ethnic differences.

Show MeSH

Related in: MedlinePlus

Curvature effects for a) age, b) period and c) cohort from full age-period-cohort model. (First cohort 1891–1895 and last cohort 1971–1975 are not shown as they are only based on one observation).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC1636657&req=5

Figure 3: Curvature effects for a) age, b) period and c) cohort from full age-period-cohort model. (First cohort 1891–1895 and last cohort 1971–1975 are not shown as they are only based on one observation).

Mentions: An age-period-cohort model provided a good fit for Chinese women aged 25 to 79 and an age-cohort model provided reasonable fit for Malays while an age-drift model best fit the Indians (Table 1). Curvature effects, or rate of change effects, were further estimated in the Chinese and Malays. All three ethnic groups had similar age curvature effects (Figure 3a). Period curvature effects (i.e. deviations of the period estimates from the linear periodic trend) were minimal in magnitude (Figure 3b), while large cohort curvature effects suggested departure from linear cohort trends (Figure 3c) for the Chinese and Malays, indicative of dominant cohort curvature effect.


Ethnic differences in the time trend of female breast cancer incidence: Singapore, 1968-2002.

Sim X, Ali RA, Wedren S, Goh DL, Tan CS, Reilly M, Hall P, Chia KS - BMC Cancer (2006)

Curvature effects for a) age, b) period and c) cohort from full age-period-cohort model. (First cohort 1891–1895 and last cohort 1971–1975 are not shown as they are only based on one observation).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC1636657&req=5

Figure 3: Curvature effects for a) age, b) period and c) cohort from full age-period-cohort model. (First cohort 1891–1895 and last cohort 1971–1975 are not shown as they are only based on one observation).
Mentions: An age-period-cohort model provided a good fit for Chinese women aged 25 to 79 and an age-cohort model provided reasonable fit for Malays while an age-drift model best fit the Indians (Table 1). Curvature effects, or rate of change effects, were further estimated in the Chinese and Malays. All three ethnic groups had similar age curvature effects (Figure 3a). Period curvature effects (i.e. deviations of the period estimates from the linear periodic trend) were minimal in magnitude (Figure 3b), while large cohort curvature effects suggested departure from linear cohort trends (Figure 3c) for the Chinese and Malays, indicative of dominant cohort curvature effect.

Bottom Line: While our analyses provided some evidence that an age-drift model described the trend seen in the Indians, age-period-cohort model and age-cohort model had the best fit for the Chinese and Malays aged 25 to 79 respectively.The observed dissimilarity among ethnic groups suggests ethnic differences in exposure or response to certain risk factors.It is likely that longer and subtler differences in childbearing trends and other risk factors may further explain these ethnic differences.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centre for Molecular Epidemiology, National University of Singapore and Genome Institute of Singapore, Singapore. cmesx@nus.edu.sg <cmesx@nus.edu.sg>

ABSTRACT

Background: From 1968 to 2002, Singapore experienced an almost three-fold increase in breast cancer incidence. This increase appeared to be different across the three main ethnic groups: Chinese, Malays and Indians. This paper used age-period-cohort (APC) modelling, to determine the effects of age at diagnosis, calendar period, and birth cohort on breast cancer incidence for each ethnic group.

Methods: This study included all breast cancer cases (n = 15,269) in the three ethnic groups, reported to the Singapore Cancer Registry from 1968 to 2002 between the ages 25 to 79. Age-specific fertility rates from the Department of Statistics were used to explore the role of fertility.

Results: In the 1970s, Indian women had the highest age-standardized breast cancer but by the mid-1980s the highest rates were seen among the Chinese. Remarkable differences were seen in the age-specific incidence rates by ethnic groups. After age 49, the incidence rates for the Chinese and Malays leveled off whereas it continued to rise in the Indians. While our analyses provided some evidence that an age-drift model described the trend seen in the Indians, age-period-cohort model and age-cohort model had the best fit for the Chinese and Malays aged 25 to 79 respectively. Overall, Chinese and Malay women born in later cohorts were at increased risk of developing breast cancer relative to their counterparts in the earlier cohorts. The three ethnic groups experienced similar changes in their fertility in the 1970s, which likely explained much of the increase in their breast cancer incidence but not the ethnic differences. There was a stronger inverse association between total fertility rate and pre-menopausal breast cancer incidence in the Chinese and Malays than the Indians.

Conclusion: The observed dissimilarity among ethnic groups suggests ethnic differences in exposure or response to certain risk factors. It is likely that longer and subtler differences in childbearing trends and other risk factors may further explain these ethnic differences.

Show MeSH
Related in: MedlinePlus