Liver cancer life expectancy

ABSTRACT

Background: The US immigrant population has grown considerably in the last three decades, from 9.6 million in 1970 to 32.5 million in 2002. However, this unprecedented population rise has not been accompanied by increased immigrant health monitoring. In this study, we examined the extent to which US- and foreign-born blacks, whites, Asians, and Hispanics differ in their health, life expectancy, and mortality patterns across the life course.

Methods: We used National Vital Statistics System (1986-2000) and National Health Interview Survey (1992-1995) data to examine nativity differentials in health outcomes. Logistic regression and age-adjusted death rates were used to examine differentials.

Results: Male and female immigrants had, respectively, 3.4 and 2.5 years longer life expectancy than the US-born. Compared to their US-born counterparts, black immigrant men and women had, respectively, 9.4 and 7.8 years longer life expectancy, but Chinese, Japanese, and Filipino immigrants had lower life expectancy. Most immigrant groups had lower risks of infant mortality and low birthweight than the US-born. Consistent with the acculturation hypothesis, immigrants' risks of disability and chronic disease morbidity increased with increasing length of residence. Cancer and other chronic disease mortality patterns for immigrants and natives varied considerably, with Asian Immigrants experiencing substantially higher stomach, liver and cervical cancer mortality than the US-born. Immigrants, however, had significantly lower mortality from lung, colorectal, breast, prostate and esophageal cancer, cardiovascular disease, cirrhosis, diabetes, respiratory diseases, HIV/AIDS, and suicide.

Interpretation: Migration selectivity, social support, socio-economic, and behavioural characteristics may account for health differentials between immigrants and the US-born.

The United States (US) immigrant population has grown considerably in the last three decades, from 9.6 million in 1970 to 32.5 million in 2002.1 Immigrants now represent 11.5% of the US population, the highest percentage in seven decades (Figure 1).1-3 The rapid increase in the immigrant population since 1970 reflects large-scale immigration from Latin America and Asia.1-5 More than half of all US immigrants are from Latin America and over a quarter of all immigrants hail from Asia. Europeans, who accounted for the majority of immigrants before 1965, currently represent 14% of the total US immigrant population.1

The unprecedented rise in the US immigrant population has not been accompanied by an increase in monitoring health and mortality patterns among immigrants of various ethnic and national origins.6-8 Most national surveillance data systems in the United States do not routinely report health statistics by immigrant status. For surveillance databases that include immigrant/nativity status as a data item, analyses of immigrant health statistics by socioeconomic, demographic, and health services characteristics are hampered by the unavailability of the appropriate population denominator data and/or by an incomplete reporting of immigrant status. Moreover, the substantial ethnic, cultural, and linguistic diversity of the current US immigrant population poses a special challenge to the systematic monitoring of data on immigrant health and well-being.

In this study, we examine the extent to which US- and foreign-born blacks, Asians, Hispanics, and non-Hispanic whites in the United States differ in their health and mortality patterns across the life course, using three large federal data systems: National Vital Statistics System (NVSS), National Health Interview Survey (NHIS), and US Decennial Census. We examined nativity differentials for a variety of measures: life expectancy, infant mortality rate (IMR), low birthweight (LBW), activity limitation, chronic disease prevalence (morbidity), number of bed disability days, and mortality from major causes of death.

DATA AND METHODS

Data for life expectancy and mortality analyses came from the mortality component of the NVSS.9 To compute stable death rates and life expectancy estimates, nine years of mortality data from 19861994 were pooled. Population denominator data by age, sex, race/ethnicity, and nativity came from the 1990 US Decennial Census.10-12 Death rates were age-adjusted by the direct method using the 2000 US population as standard.9 We computed average annual rates of mortality from allcauses combined, and from all major cancers and causes of death: lung, colorectal, stomach, prostate, breast, cervical, esophageal, and liver cancers; and cardiovascular diseases (CVD), respiratory diseases, cirrhosis, diabetes, suicide, homicide, and unintentional injuries. Life expectancy estimates were calculated via the standard life table methodology by converting observed age-specific death rates into life table probabilities of dying.13 The 1998-2000 data on IMR and LBW were derived from the natality component of the NVSS.14,15 Logistic regression models that account for complex sampling designs were fitted to the 1992-1995 NHIS data to estimate relative risks of chronic disease prevalence, bed disability, and activity limitation among 39 ethnic-immigrant groups after adjustment for a variety of socio-economic and demographic factors.16-20 The NHIS is a national sample household survey in which data on socio-economic, demographic, behavioural, morbidity, health, and health care characteristics are collected via personal household interviews.21 The survey uses a multistage probability design and is representative of the civilian noninstitutionalized population of the United States. Detailed descriptions of the NVSS and NHIS have been provided elsewhere.9,21,22

RESULTS

During 1986-1994, male and female immigrants had on average 3.4 and 2.5 years longer life expectancy at birth than did the US-born (Figure 2). Black and Hispanic immigrant men and women had, respectively, 9.4, 4.3, 7.8, and 3.0 years longer life expectancy than their US-born counterparts. Chinese, Japanese, and Filipino immigrants, however, had lower life expectancy than their US-born counterparts. Immigrants had, respectively, 18% and 27% lower LBW and infant mortality rates during 1998-2000, with Chinese and Koreans experiencing the lowest LBW and infant mortality risks (30% and 52% lower, respectively) compared to their US-born counterparts (Table I). Consistent with the acculturation hypothesis, risks of disability and chronic disease morbidity during 1992-1995 among immigrants of various ethnic backgrounds, although significantly lower than those for the US-born non-Hispanic whites, increased with increasing duration of residence in the United States. For example, compared to US-born non-Hispanic whites of similar socio-economic backgrounds, the risk of chronic medical condition was, respectively, 69%, 56%, and 37% lower among recent Chinese immigrants (those who immigrated to the US in the previous 15 years), long-term Chinese immigrants (those who immigrated to the US more than 15 years previous), and US-born Chinese (Table II).

Cancer and other chronic disease mortality patterns for immigrants and the US-born also varied considerably (Tables 111 and IV). Black male and female immigrants had at least 35% lower total cancer mortality than US-born blacks. However, Chinese male immigrants and Japanese female immigrants had, respectively, 35% and 25% higher total cancer mortality than their US-born counterparts. Black immigrants had 69% lower lung cancer mortality than US-born blacks. On the other hand, Chinese male immigrants and Japanese female immigrants had, respectively, 51% and 42% higher lung cancer mortality than their US-born counterparts. Stomach cancer mortality was almost twice as high for immigrants, especially Chinese immigrants, as for the US-born. Liver cancer mortality was substantially higher for immigrants, with Chinese immigrant men and Japanese immigrant women in particular experiencing three times higher mortality than their US-born counterparts. While prostate cancer mortality was generally lower among immigrants, Filipino immigrants had a 3.1 times higher mortality rate than US-born Filipinos. Breast cancer mortality was substantially lower among immigrants, with Chinese, Japanese, and black immigrant women experiencing, respectively, 35%, 34%, and 30% lower mortality than their US-born counterparts. Compared to the US-born women, cervical cancer mortality was substantially higher among Asian/Pacific Islander (API) immigrants, especially Japanese immigrant women, who had 146% higher mortality than US-born Japanese women.