Mortality from lung cancer and chronic obstructive pulmonary disease in New Mexico, 1958-82

Racial and Ethnic Minorities Have a Lower Prevalence of Airflow Obstruction than Non-Hispanic Whites

Racial and ethnic disparities in chronic obstructive pulmonary disease (COPD) are not well-studied. Our objective was to examine differences in limited COPD-related outcomes between three minority groups-African Americans (AAs), Hispanics, and American Indians (AIs) versus non-Hispanic Whites (NHWs), as the referent group, in separate cohorts. Separate cross-sectional evaluations were performed of three US-based cohorts of subjects at risk for COPD: COPDGene Study with 6,884 NHW and 3,416 AA smokers; Lovelace Smokers' Cohort with 1,598 NHW and 378 Hispanic smokers; and Mining Dust Exposure in the United States Cohort with 2,115 NHW, 2,682 Hispanic, and 2,467 AI miners. Prebronchodilator spirometry tests were performed at baseline visits using standard criteria. The primary outcome was the prevalence of airflow obstruction. Secondary outcomes were self-reported physician diagnosis of COPD, chronic bronchitis, and modified Medical Research Council dyspnea score. All minority groups had a lower prevalence of airflow obstruction than NHWs (adjusted ORs varied from 0.29 in AIs to 0.85 in AAs; p < 0.01 for all analyses). AAs had a lower prevalence of chronic bronchitis than NHWs. In our study, all minority groups had a lower prevalence of airflow obstruction but a greater level of self-reported dyspnea than NHWs, and covariates did not explain this association. A better understanding of racial and ethnic differences in smoking-related and occupational airflow obstruction may improve prevention and therapeutic strategies.

Non-communicable diseases in migrants: an expert review

BACKGROUND

Non-communicable diseases (NCDs) remain a major challenge in the 21st century. High-income countries (HICs) populations are ethnically and culturally diverse due to international migration. Evidence suggests that NCDs rates differ between migrants and the host populations in HICs. This paper presents a review of NCDs burden among migrant groups in HICs in Europe, North America and Australia with a major focus on cardiovascular diseases (CVDs), cancer and diabetes.

METHODS

We performed a narrative review consisting of scholarly papers published between 1960 until 2018.

RESULTS

CVD risk differs by country of origin, country of destination and duration of residence. For example, stroke is more common in sub-Sahara African and South-Asian migrants, but lower in North African and Chinese migrants. Chinese migrants, however, have a higher risk of haemorrhagic stroke despite the lower rate of overall stroke. Coronary heart disease (CHD) is more common in South-Asian migrants, but less common in sub-Saharan and north African migrants although the lower risk of CHD in these population is waning. Diabetes risk is higher in all migrants and migrants seem to develop diabetes at an earlier age than the host populations. Migrants in general have lower rates of overall cancer morbidity and mortality than the host populations in Europe. However, migrants have a higher infectious disease-related cancers than the host populations in Europe. In North America, the picture is more complex. Data from cross-national comparisons indicate that migration-related lifestyle changes associated with the lifestyle of the host population in the country of settlement may influence NCDs risk among migrants in a very significant way.

CONCLUSION

With exception of diabetes, which is consistently higher in all migrant groups than in the host populations, the burden of NCDs among migrants seems to depend on the migrant group, country of settlement and NCD type. This suggests that more work is needed to disentangle the key migration-related lifestyle changes and contextual factors that may be driving the differential risk of NCDs among migrants in order to assist prevention and clinical management of NCDs in these populations.

The Protective Effect of Hispanic Ethnicity on Chronic Obstructive Pulmonary Disease Mortality is Mitigated by Smoking Behavior

RATIONALE

Studies in Hispanic/Latino populations have shown ethnicity to be either a predictive or protective factor for COPD mortality and it is unclear whether this disagreement is attributable to ethnic differences in smoking rates, smoking behavior or differences in genetic susceptibility.

OBJECTIVES

This study will examine the role of smoking behavior as a means of explaining differences in risk for COPD mortality between Hispanics and non-Hispanic whites.

METHODS

Participants were recruited into a cohort study from the San Luis Valley in Colorado beginning in the early 1980's and followed for mortality until 2012. COPD and cardiovascular disease are often comorbid conditions and account for the competing risk of CVD in the analysis of COPD mortality. Mortality searches were conducted regularly and all ICD codes were collected for mortality event. Primary and secondary causes of each event were assessed using appropriate codes.

RESULTS

Hispanic current smokers did not differ from NHW current smokers in years smoked (p=0.6) but Hispanic former smokers accumulated more years smoked compared to NHW former smokers (22 vs. 20, p=0.047). Hispanic ethnicity was significantly protective for COPD mortality adjusting for age, gender, pre-existing emphysema, hypertension and smoking status and accounting for the effect of CVD mortality (RR=0.58, 95% C.I. 0.34-0.99, p=0.035). Further adjustment for smoking behavior mitigated this effect.

CONCLUSIONS

The lower COPD mortality seen in Hispanic smokers may be due lower cumulative exposure to tobacco smoke. Thus, smoking behavior may play a key role in explaining differences in COPD mortality as they relate to Hispanic ethnicity.

Obstructive lung disease in Mexican Americans and non-Hispanic whites: an analysis of diagnosis and survival in the National Health and Nutritional Examination Survey III Follow-up Study

BACKGROUND

Although obstructive lung disease (OLD), which includes COPD, affects all the populations, Hispanics seem to be protected against COPD development and progression. Whether this advantage translates into a survival benefit for this population is unknown. We aimed to determine the risk for OLD in Mexican Americans, the largest US Hispanic subgroup, compared with non-Hispanic whites and to assess all-cause mortality in subjects with OLD.

METHODS

We assessed the relationships between Mexican American ethnicity and spirometric OLD and risk of death among 6,456 US adults aged ≥ 40 years who participated in the Third National Health and Nutritional Examination Survey Follow-up Study. We used logistic and Cox regression analyses to estimate the OR for OLD among Mexican Americans and the hazard ratio (HR) for all-cause mortality among Mexican Americans with OLD, respectively.

RESULTS

After adjustment for demographic factors, socioeconomic status, and COPD risk factors, Mexican Americans had decreased odds of OLD diagnosis compared with whites (OR, 0.72 [95% CI, 0.54-0.95]). Among the 1,734 participants with OLD, 1,054 (60.8%) died during median follow-up of 12 years. In an adjusted model, Mexican Americans had no advantage in mortality from all causes (HR, 0.88 [95% CI, 0.69-1.13]). After accounting for the fact that some Mexican Americans may have moved back to Mexico and died there (thus, had no US death certificate), there was still no difference in mortality between these groups.

CONCLUSIONS

Although Mexican Americans appear to have lower risk for OLD, subjects of this ethnicity with OLD do not seem to have a survival advantage.

New Mexican Hispanic smokers have lower odds of chronic obstructive pulmonary disease and less decline in lung function than non-Hispanic whites

RATIONALE

The epidemiology of cigarette smoking-related chronic obstructive pulmonary disease (COPD) is not well characterized in Hispanics in the United States. Understanding how ethnicity influences COPD is important for a number of reasons, from informing public health policies to dissecting the genetic and environmental effects that contribute to disease.

OBJECTIVES

The present study assessed differences in risk between Hispanics and non-Hispanic whites for longitudinal and cross-sectional COPD phenotypes. Genetic ancestry was used to verify findings based on self-reported ethnicity. Hispanics in New Mexico are primarily differentiated from non-Hispanic whites by their proportion of Native American ancestry.

METHODS

The study was performed in a New Mexican cohort of current and former smokers. Self-reported Hispanic and non-Hispanic white ethnicity was validated by defining genetic ancestry proportions at the individual level using 48 single-nucleotide polymorphism markers. Self-reported ethnicity and genetic ancestry were independently used to assess associations with cross-sectional and longitudinal measures of lung function. Multivariable models were adjusted for indicators of smoking behavior.

MEASUREMENTS AND MAIN RESULTS

Self-reported Hispanic ethnicity was significantly associated with lower odds of COPD (odds ratio, 0.49; 95% confidence interval, 0.35-0.71; P = 0.007), and this protection was validated by the observation that Hispanic smokers have reduced risk of rapid decline in lung function (odds ratio, 0.48; 95% confidence interval, 0.30-0.78; P = 0.003). Similar findings were noted when Native American genetic ancestry proportions were used as predictors instead of self-report of Hispanic ethnicity.

CONCLUSIONS

Hispanic ethnicity is inversely associated with cross-sectional and longitudinal spirometric COPD phenotypes even after adjustment for smoking. Native American genetic ancestry may account for this "Hispanic protection."

Wood smoke exposure and gene promoter methylation are associated with increased risk for COPD in smokers

RATIONALE

Wood smoke-associated chronic obstructive pulmonary disease (COPD) is common in women in developing countries but has not been adequately described in developed countries.

OBJECTIVES

Our objective was to determine whether wood smoke exposure was a risk factor for COPD in a population of smokers in the United States and whether aberrant gene promoter methylation in sputum may modify this association.

METHODS

For this cross-sectional study, 1,827 subjects were drawn from the Lovelace Smokers' Cohort, a predominantly female cohort of smokers. Wood smoke exposure was self-reported. Postbronchodilator spirometry was obtained, and COPD outcomes studied included percent predicted FEV₁, airflow obstruction, and chronic bronchitis. Effect modification of wood smoke exposure with current cigarette smoke, ethnicity, sex, and promoter methylation of lung cancer-related genes in sputum on COPD outcomes were separately explored. Multivariable logistic and poisson regression models were used for binary and rate-based outcomes, respectively.

MEASUREMENTS AND MAIN RESULTS

Self-reported wood smoke exposure was independently associated with a lower percent predicted FEV₁ (point estimate [± SE] -0.03 ± 0.01) and a higher prevalence of airflow obstruction and chronic bronchitis (odds ratio, 1.96; 95% confidence interval, 1.52-2.52 and 1.64 (95% confidence interval, 1.31-2.06, respectively). These associations were stronger among current cigarette smokers, non-Hispanic whites, and men. Wood smoke exposure interacted in a multiplicative manner with aberrant promoter methylation of the p16 or GATA4 genes on lower percent predicted FEV₁.

CONCLUSIONS

These studies identify a novel link between wood smoke exposure and gene promoter methylation that synergistically increases the risk for reduced lung function in cigarette smokers.

Wood smoke exposure and gene promoter methylation are associated with increased risk for COPD in smokers

RATIONALE

Wood smoke-associated chronic obstructive pulmonary disease (COPD) is common in women in developing countries but has not been adequately described in developed countries.

OBJECTIVES

Our objective was to determine whether wood smoke exposure was a risk factor for COPD in a population of smokers in the United States and whether aberrant gene promoter methylation in sputum may modify this association.

METHODS

For this cross-sectional study, 1,827 subjects were drawn from the Lovelace Smokers' Cohort, a predominantly female cohort of smokers. Wood smoke exposure was self-reported. Postbronchodilator spirometry was obtained, and COPD outcomes studied included percent predicted FEV₁, airflow obstruction, and chronic bronchitis. Effect modification of wood smoke exposure with current cigarette smoke, ethnicity, sex, and promoter methylation of lung cancer-related genes in sputum on COPD outcomes were separately explored. Multivariable logistic and poisson regression models were used for binary and rate-based outcomes, respectively.

MEASUREMENTS AND MAIN RESULTS

Self-reported wood smoke exposure was independently associated with a lower percent predicted FEV₁ (point estimate [± SE] -0.03 ± 0.01) and a higher prevalence of airflow obstruction and chronic bronchitis (odds ratio, 1.96; 95% confidence interval, 1.52-2.52 and 1.64 (95% confidence interval, 1.31-2.06, respectively). These associations were stronger among current cigarette smokers, non-Hispanic whites, and men. Wood smoke exposure interacted in a multiplicative manner with aberrant promoter methylation of the p16 or GATA4 genes on lower percent predicted FEV₁.

CONCLUSIONS

These studies identify a novel link between wood smoke exposure and gene promoter methylation that synergistically increases the risk for reduced lung function in cigarette smokers.

The role of tobacco in cancer health disparities

Although public health efforts have dramatically reduced the prevalence of smoking in the past several decades, smoking remains the leading cause of preventable morbidity and mortality in the United States. Moreover, tobacco use is becoming increasingly concentrated among individuals with the lowest levels of education, income, and occupational status. Profound racial/ethnic and socioeconomic status (SES) disparities exist for tobacco-related cancer incidence and mortality, and for access to and quality of cancer treatment. Furthermore, racial/ethnic minority and low SES smokers have greater difficulty quitting smoking, are less likely to use effective resources for quitting, and have limited access to evidence-based cessation treatments. Widespread implementation of population-based tobacco cessation approaches may have had the unintended effect of increasing tobacco-related cancer health disparities. It is crucial that vulnerable populations of smokers be provided with effective and accessible treatments for tobacco dependence, as this would have a profound impact on reducing tobacco-related cancer health disparities.

Human papillomavirus genotype distributions: implications for vaccination and cancer screening in the United States

BACKGROUND

Limited data are available describing human papillomavirus (HPV) genotype distributions in cervical cancer in the United States. Such studies are needed to predict how HPV vaccination and HPV-based screening will influence cervical cancer prevention.

METHODS

We used the New Mexico Surveillance, Epidemiology, and End Results Registry to ascertain cases of in situ (n = 1213) and invasive (n = 808) cervical cancer diagnosed during 1985-1999 and 1980-1999, respectively, in the state of New Mexico. HPV genotyping was performed using two polymerase chain reaction-based methods on paraffin-embedded tissues from in situ and invasive cancers and on cervical Papanicolaou test specimen from control subjects (ie, women aged 18-40 years attending clinics for routine cervical screening [n = 4007]). Relative risks for cervical cancer were estimated, and factors associated with age at cancer diagnosis and the prevalence of HPV genotypes in cancers were examined.

RESULTS

The most common HPV genotypes detected in invasive cancers were HPV type 16 (HPV16, 53.2%), HPV18 (13.1%), and HPV45 (6.1%) and those in in situ cancers were HPV16 (56.3%), HPV31 (12.6%), and HPV33 (8.0%). Invasive cancer case subjects who were positive for HPV16 or 18 were diagnosed at younger ages than those who were positive for other carcinogenic HPV genotypes (mean age at diagnosis: 48.1 [95% confidence interval {CI} = 46.6 to 49.6 years], 45.9 [95% CI = 42.9 to 49.0 years], and 52.3 years [95% CI = 50.0 to 54.6 years], respectively). The proportion of HPV16-positive in situ and invasive cancers, but not of HPV18-positive cancers, declined with more recent calendar year of diagnosis, whereas the proportion positive for carcinogenic HPV genotypes other than HPV18 increased.

CONCLUSIONS

HPV16 and 18 caused the majority of invasive cervical cancer in this population sample of US women, but the proportion attributable to HPV16 declined over the last 20 years. The age at diagnosis of HPV16- and HPV18-related cancers was 5 years earlier than that of cancers caused by carcinogenic HPV genotypes other than HPV16 and 18, suggesting that the age at initiation of cervical screening could be delayed in HPV-vaccinated populations.

Difference in airflow obstruction between Hispanic and non-Hispanic White female smokers

Smoking-related respiratory diseases are a major cause of morbidity and mortality. However, the relationship between smoking and respiratory disease has not been well-studied among ethnic minorities in general and among women in particular. The objective of this cross-sectional study was to evaluate the risk of airflow obstruction and to assess lung function among Hispanic and non-Hispanic White (NHW) female smokers in a New Mexico cohort. Participants completed a questionnaire detailing smoking history and underwent spirometry testing. Outcomes studied included airflow obstruction, selected lung function parameters, and chronic mucus hyper-secretion. Chi square, logistic, and linear regression techniques were utilized. Of the 1,433 eligible women participants, 248 (17.3%) were Hispanic; and 319 had airflow obstruction (22.3%). Hispanic smokers were more likely to be current smokers, and report lower pack-years of smoking, compared to NHW smokers (p < 0.05 for all analyses). Further, Hispanic smokers were at a reduced risk of airflow obstruction compared to NHW smokers, with an O.R. of 0.51, 95% C.I. 0.34, 0.78 (p = 0.002) after adjustment for age, BMI, pack-years and duration of smoking, and current smoking status. Following adjustment for covariates, Hispanic smokers also had a higher mean absolute and percent predicted post-bronchodilator FEV(1)/FVC ratio, as well as higher mean percent predicted FEV(1) (p < 0.05 for all analyses). Hispanic female smokers in this New Mexico-based cohort had lower risk of airflow obstruction and better lung function than NHW female smokers. Further, smoking history did not completely explain these associations.

Chronic obstructive pulmonary disease in Hispanics

Hispanics are individuals whose ancestry can be traced to Spain and/or areas previously under Spanish control (e.g., Mexico, Puerto Rico). They are a rapidly growing subset of the population of the United States and are quite diverse in their racial ancestry, country of origin, area of residence, socioeconomic status, tobacco use, and access to health care. Current evidence suggests that the prevalence and morbidity of chronic obstructive pulmonary disease (COPD) vary widely among Hispanic-American nations, with similar but limited findings among Hispanic subgroups in the United States. Potential reasons for such variation include differences in racial ancestry and genetic susceptibility, exposure to tobacco smoke and/or biomass smoke, access to health care, and disease management. Future studies of COPD in Hispanics should include large samples of subgroups that are well defined with regard to self-reported ethnicity, country of origin, area of residence, tobacco use, and socioeconomic status. Areas that need to be carefully examined include validation of COPD diagnoses for epidemiologic studies (e.g., by radiologic assessment), COPD in high-risk groups (e.g., Puerto Ricans), impact of biomass smoke (in rural areas) and air pollution (in urban areas) on COPD morbidity, effects of migration and acculturation on COPD prevalence and morbidity among Hispanic subgroups in the United States, development of reference values for spirometry, smoking cessation, and overcoming barriers to management. Public health measures, such as effective smoking prevention and cessation programs, reduction of air pollution and exposure to biomass smoke, and improved access to health care, would help reduce the burden of COPD among Hispanics in the United States and Latin America.

Carotid stenosis in a multiethnic population

BACKGROUND

Carotid stenosis is an important, treatable cause of stroke. Several population-based studies have shown ethnic differences in the prevalence of carotid atherosclerosis. This study was performed at a large multiethnic hospital to clarify these differences.

METHODS

One thousand six carotid artery ultrasounds performed by the Department of Radiology at Los Angeles County General Hospital over a 4-year period were reviewed. Patients were classified as Caucasian (n=151), Hispanic (n=515), Black (n=173), or Asian (n=167) by self-declaration and birthplace. Carotid stenosis was defined as mild (1% to 39%), moderate (40% to 59%), severe (60% to 79%), critical (80% to 99%), or total (100%).

RESULTS

Twenty and one-half percent of Caucasian patients had greater than 59% stenosis compared with 10.1% of Hispanics, 8.7% of Blacks, and 10.7% of Asians (P<0.001). Nine and two-tenths percent of Caucasians had greater than 79% stenosis compared with 4.3% of Hispanics, 2.9% of Blacks, and 2.8% of Asians (P<0.001). There were no significant differences in age or gender representations between ethnic groups, and the indications for ordering carotid duplex sonography also did not vary by race. Caucasians and Blacks had a higher prevalence of cardiac disease, smoking, and heavy alcohol abuse. Hispanics had higher rates of diabetes.

CONCLUSIONS

These results indicate that significant differences in the degree of carotid stenosis exist among ethnic groups. Caucasian patients in our series showed a statistically higher likelihood of having a severe or critical level of stenosis. These findings may have implications for the allocation of health care resources as ethnic minorities compose a greater proportion of the population.

Predictors of rehospitalization and death after a severe exacerbation of COPD

BACKGROUND

Patients who survive a severe exacerbation of COPD are at high risk of rehospitalization for COPD and death. The objective of this study was to determine predictors of these events in a large cohort of Veterans Affairs (VA) patients.

METHODS

We identified 51,353 patients who were discharged after an exacerbation of COPD in the VA health-care system from 1999 to 2003, and determined the rates of rehospitalization for COPD and death from all causes. Potential risk factors were assessed with univariate and multivariate survival analysis.

RESULTS

On average, the cohort was elderly (mean age, 69 years), predominately white (78% white, 13% black, 3% other, and 6% unknown), and male (97%), consistent with the underlying VA population. The risk of death was 21% at 1 year, and 55% at 5 years. Independent risk factors for death were age, male gender, prior hospitalizations, and comorbidities including weight loss and pulmonary hypertension; nonwhite race and other comorbidities (asthma, hypertension, and obesity) were associated with decreased mortality. The risk of rehospitalization for COPD was 25% at 1 year, and 44% at 5 years, and was increased by age, male gender, prior hospitalizations, and comorbidities including asthma and pulmonary hypertension. Hispanic ethnicity and other comorbidities (diabetes and hypertension) were associated with a decreased risk of rehospitalization.

CONCLUSIONS

Age, male gender, prior hospitalizations, and certain comorbid conditions were risk factors for death and rehospitalization in patients discharged after a severe COPD exacerbation. Nonwhite race and other comorbidities were associated with decreased risk.

Disparities in Lung Cancer: Focus on Asian Americans and Pacific Islanders, American Indians and Alaska Natives, and Hispanics and Latinos

Significant population changes in the United States are expected over the next few decades. The changing demographics inclusive of native and newly native individuals will significantly impact health care because racial and ethnic groups vary widely in their risks for disease and approach to medical care. For lung cancer specifically, racial and ethnic groups differ in smoking habits, metabolism of nicotine, presentation, stage at diagnosis, treatment received, and outcomes. This article summarizes current information on lung cancer for American and Pacific Islanders, American Indians and Alaska natives,and Hispanics and Latinos with an emphasis on tobacco use, epidemiologic issues sur-rounding acculturation and assimilation, genetic epidemiology, and disparities in treatment outcomes.

The history of uranium mining and the Navajo people

From World War II until 1971, the government was the sole purchaser of uranium ore in the United States. Uranium mining occurred mostly in the southwestern United States and drew many Native Americans and others into work in the mines and mills. Despite a long and well-developed understanding, based on the European experience earlier in the century, that uranium mining led to high rates of lung cancer, few protections were provided for US miners before 1962 and their adoption after that time was slow and incomplete. The resulting high rates of illness among miners led in 1990 to passage of the Radiation Exposure Compensation Act.

The epidemiology of lung cancer

Lung cancer continues to be the leader in cancer deaths in the United States. The incidence of lung cancer in men has slowly decreased since the late 1980s, but has just now begun to plateau in women at the end of this decade. Despite modest advances in chemotherapy for treating lung cancer, it remains a deadly disease with overall 5-yr survival rates having not increased significantly over the last 25 years, remaining at approximately 14%. Tobacco smoking causes approximately 85-90% of bronchogenic carcinoma. Environmental tobacco exposure or a second-hand smoke also may cause lung cancer in life-long non-smokers. Certain occupational agents such as arsenic, asbestos, chromium, nickel and vinyl chloride increase the relative risk for lung cancer. Smoking has an additive or multiplicative effect with some of these agents. Familial predisposition for lung cancer is an area with advancing research. Developments in molecular biology have led to growing interest in investigation of biological markers, which may increase predisposition to smoking-related carcinogenesis. Hopefully, in the future we will be able to screen for lung cancer by using specific biomarkers. Finally, dietary factors have also been proposed as potential risk modulators, with vitamins A, C and E proposed as having a protective effect. Despite the slow decline of smoking in the United States, lung cancer will likely continue its devastation for years to come.

Epidemiology of lung cancer

There are few relationships in the epidemiology of cancer between an exposure and disease that are as consistent as those observed between tobacco and lung cancer. The health consequences of tobacco use are not limited to lung cancer; the 1990 Surgeon General's Report described that the use of cigarettes was the leading cause of avoidable mortality in the United States, with about 434,000 preventable deaths per year. Although a majority of the adults in the United States are current or former smokers, smoking cessation and prevention efforts have been successful, although currently about one in four adults still smoke cigarettes. The decline in ever-smoking has reached a plateau in the past few years, however, and rates of teenage smoking have begun to increase. In 1997, smoking rates among high school students in the United States were 32% higher compared with 1991. As noted by Cinciripini et al, adult smokers who quit or die are being replaced by children who smoke. Until recently, lung cancer control efforts primarily have focused on smoking prevention in youth and cessation among adults, with little obvious potential for reducing deaths through early detection. With the recent publication of early results from the Early Lung Cancer Action Project showing remarkably more favorable screening performance compared with chest radiography, the potential to detect lung cancer early and save lives is being revisited. Ultimately, the preferred disease control strategy is the prevention of lung cancer through the elimination of tobacco use altogether, but for the foreseeable future a legacy of decades of tobacco use in a significant proportion of the US population means we are still challenged to develop public health strategies to reduce deaths and suffering from those destined to develop lung cancer.

Mortality among Navajo uranium miners

OBJECTIVES

To update mortality risks for Navajo uranium miners, a retrospective cohort mortality study was conducted of 757 Navajos from the cohort of Colorado Plateau uranium miners.

METHODS

Vital status was followed from 1960 to 1990. Standardized mortality ratios were estimated, with combined New Mexico and Arizona non-White mortality rates used for comparison. Cox regression models were used to evaluate exposure-response relationships.

RESULTS

Elevated standardized mortality ratios were found for lung cancer (3.3), tuberculosis (2.6), and pneumoconioses and other respiratory diseases (2.6). Lowered ratios were found for heart disease (0.6), circulatory disease (0.4), and liver cirrhosis (0.5). The estimated relative risk for a 5-year duration of exposure vs none was 3.7 for lung cancer, 2.1 for pneumoconioses and other respiratory diseases, and 2.0 for tuberculosis. The relative risk for lung cancer was 6.9 for the midrange of cumulative exposure to radon progeny compared with the least exposed.

CONCLUSIONS

Findings were consistent with those from previous studies. Twenty-three years after their last exposure to radon progeny, these light-smoking Navajo miners continue to face excess mortality risks from lung cancer and pneumoconioses and other respiratory diseases.

Mortality differences between elderly Mexican Americans and non-Hispanic whites in San Antonio, Texas

OBJECTIVE

To identify differences in causes of death between elderly Mexican Americans (MA) and non-Hispanic whites (NHW).

DESIGN

Retrospective death certificate review.

SUBJECTS

Elderly Mexican Americans and non-Hispanic Whites age 65 and over who died in Bexar County, Texas during 1989.

MEASURES

Data obtained from chart review included age, sex, race/ethnicity, and cause of death. Age-adjusted and cause-specific mortality rates, odds ratios (OR), and 95% confidence intervals (CI) were calculated.

RESULTS

Mexican Americans were at greater risk of dying in nine of the thirty causes of death examined. The mortality rates of MA subjects were higher than those of NHW from death caused by diabetes (OR = 3.19, CI = 2.27-4.49), renal failure (OR = 2.06, CI = 1.44-2.94), congestive heart failure (OR = 1.50, CI = 1.44-2.94), and multiple systemic diseases (OR = 2.59, CI = 1.89-3.57). Among the male subjects, MA had a greater risk than NHW of dying from myocardial infarction (OR = 1.83, CI = 1.15-2.90), coronary disease (OR = 1.37, CI = 1.07-1.75) and septicemia/pyuria (OR = 2.12, CI = 1.09-4.10). Among female subjects, MA had a greater likelihood of dying from cirrhosis (OR = 3.03, CI = 1.00-9.29). For only one of the causes of death was the risk lower among MA than NHW: MA female subjects had a lesser chance of dying from the chronic obstructive pulmonary disease (COPD) than NHW females (OR = 0.36, CI = 0.18-0.72).

CONCLUSION

Mexican American elders have a greater risk of dying from non-insulin dependent diabetes mellitus and renal failure than their NHW counterparts. Elderly MA men have a greater risk of dying from cardiovascular disease than their NHW counterparts. Mexican American women may have a greater risk of dying from cirrhosis, but a lower risk of dying from complications of COPD. Finally, death from ill defined causes, such as multiple systemic diseases, may be a major under-acknowledged cause of death among older MA.

Mortality among workers in the diatomaceous earth industry

A cohort mortality study was conducted among workers from two plants in the diatomaceous earth mining and processing industry in California. Diatomaceous earth consists of the skeletal remains of diatoms. Exposure to amorphous (non-crystalline) and crystalline silica in the form of quartz results from open pit mining and exposure to crystalline silica (principally cristobalite) occurs in the processing of the material. Lung cancer and non-malignant respiratory diseases have been the health outcomes of greatest concern. The main study cohort included 2570 white men (533 Hispanic and 2017 non-Hispanic workers) who were employed for at least 12 months cumulative service in the industry and who had worked for at least one day during the follow up period, 1942-87. Vital status was ascertained for 91% of the cohort and death certificate information was retrieved for 591 of 628 (94%) identified deaths. The all causes combined standardised mortality ratio (SMR) was slightly increased (SMR = 1.12; 628 observed) compared with rates among US white males. The principal contributors to this excess were increased risks from lung cancer (SMR = 1.43; 59 observed) and non-malignant respiratory disease (NMRD) excluding infectious diseases and pneumonia (SMR = 2.59; 56 observed). The excess of lung cancer persisted when local county rates were used for comparison (SMR = 1.59). Internal rate comparisons by Poisson regression analysis were conducted to assess potential dose-response relations for lung cancer and NMRDs. Mortality trends were examined in relation to duration of employment in dust exposed jobs and with respect to an index of cumulative exposure to crystalline silica. The crystalline silica index was a semiquantitative measure that combined information on duration of exposure, differences in exposure intensity between jobs and calendar periods, the crystalline content of the various product mixes, and the use of respiratory protection devices. Increasing gradients of risk were detected for lung cancer and NMRD with both exposure indices. The relative risk trends for lung cancer and NMRD with crystalline silica exposure lagged 15 years were respectively: 1.00, 1.19, 1.37, and 2.74, and 1.00, 1.13, 1.58, and 2.71. Based on a review of available but limited data on cigarette smoking in the cohort and from application of indirect methods for assessing confounding variables, it seems unlikely that smoking habits could account for all of the association between exposure to dust and lung cancer. The intense and poorly controlled dust exposures encountered before the 1950s were probably the most aetiologically significant contributors to risks from lung cancer and NMRDs. The absence of an excess of lung cancer among workers hired since 1960, and the finding of no deaths attributed to pneumoconiosis as an underlying cause of death among workers hired since 1950 indicate that exposure reductions in the industry during the past 40 years have been successful in reducing excess risks to workers. Further mortality follow up of the cohort and the analysis of radiographic data will be needed to determine conclusively the long term patterns of disease risks in this industry.

The epidemiology of lung cancer

Lung cancer rates and mortality have risen in epidemic proportions in the United States and other industrialized nations during the 20th century. Case-control and cohort studies performed in the 1950s and 1960s firmly established cigarette smoking as the single greatest risk factor for lung cancer. In the United States, overall lung cancer mortality rates in men and women rose progressively from the 1950s. Fortunately, lung cancer incidence and mortality are now declining in middle-aged men. Smoking has significantly increased lung cancer rates among women and is on the rise in developing countries. Environmental agents found in the home and workplace, including radon and asbestos, have also been shown to increase lung cancer risk in both smokers and nonsmokers. Government regulations have helped curtail quantities of these and other atmospheric carcinogens. Efforts to reduce lung cancer risk must be continued and their scope expanded in order to have a global impact on the incidence and mortality of this fatal malignancy.

Dietary micronutrients and cervical dysplasia in southwestern American Indian women

American Indian women in the Southwest have high rates of cervical cancer and cervical dysplasia in contrast to low rates of cancers for other sites. Despite their high rates of cervical disease, no published information has specifically examined risk factors for cervical cancer or cervical dysplasia among American Indian women. We carried out a pilot case-control study of cervical dysplasia in southwestern American Indian women to examine the relationship of dietary intake of vitamin C, folacin, vitamin E, carotenoids, and retinol with cervical cytological abnormalities. Twenty-four-hour dietary recalls were collected from women with cervical dysplasia (n = 42) and women with normal cervical cytologies (n = 58). Macro- and micronutrient intake was estimated from these recalls utilizing food and nutrient data from the USDA Survey Nutrient Database. Although mean differences between cases and controls were not statistically significant for any of the micronutrients examined, women with low intake of vitamin C, folacin, and vitamin E were at increased risk of having cervical dysplasia when the data were analyzed as stratified for level of intake (low vs. high intake odds ratios were 3.0 for vitamin C, 3.3 for folacin, and 1.7 for vitamin E). The relationship between dietary micronutrients and cervical dysplasia among American Indian women warrants further investigation using more refined measures of dietary micronutrient intake, together with consideration of other risk factors for cervical disease.

Cervical papillomavirus infection and cervical dysplasia in Hispanic, Native American, and non-Hispanic white women in New Mexico

BACKGROUND

Human papillomavirus infections of the cervix are found with varying frequencies in different populations worldwide, and have been associated with cervical cytologic abnormalities.

METHODS

We studied 1,603 randomly selected Hispanic, Native American, and non-Hispanic White women in New Mexico to determine the prevalence of cervical HPV infection in these ethnic groups, and its association with Pap smear abnormalities, using a new commercial dot-blot hybridization assay.

RESULTS

Nine percent of all women screened had evidence of cervical HPV infection (13.7% of non-Hispanic White women, 9.7% of Hispanics, and 6.6% of Native American women). Prevalence was higher in younger women ages 14-19 years than in older age groups. Over half of women with cervical HPV infection (n = 145) had normal Pap smears. The proportion of infected women increased among those with more advanced cytopathologic abnormalities; 5.6 percent with normal Pap smears had cervical HPV vs 66.7 percent with moderate-severe dysplasia.

CONCLUSIONS

Cervical HPV infection is common among New Mexico clinic attendees, varies in prevalence among the three major ethnic groups, and is strongly associated with cervical cytopathologic abnormalities.

Patterns of cigarette smoking among Hispanics in the United States: results from HHANES 1982-84

In the 1982-84 Hispanic Health and Nutrition Examination Survey, the prevalence of cigarette smoking was examined among Mexican Americans, Puerto Ricans, and Cuban Americans in the United States. Among 20-74 years olds, the age-adjusted smoking rates for Mexican American, Puerto Rican, and Cuban American men were high--42.5, 39.8, and 41.6 percent, respectively. Quite striking among Cuban American men was the high smoking rate among 20-34 year olds (50.1 percent), the highest smoking rate in the three Hispanic groups compared. The age-adjusted smoking rates for Mexican American, Puerto Rican, and Cuban American women were much lower than those for men-23.8, 30.3, and 24.4 percent, respectively. Both Puerto Rican and Cuban American men were more likely to be heavy smokers (52.3 and 64.1 percent, respectively, smoking a pack or more a day) as compared to the Mexican Americans (33.8 percent smoking a pack or more a day). The pattern was the same for women, with Mexican American women being lighter smokers (18.8 percent smoking a pack or more a day) as compared to heavy smoking among Puerto Rican and Cuban American women (35.1 and 48.6 percent, respectively, smoking a pack or more a day). Given the health hazards of smoking, future research and intervention are required for those groups with high exposure to cigarette smoking.

The major respiratory diseases of American Indians

The most prominent respiratory diseases of American Indian adults are pneumonia, cancer of the lung, chronic obstructive pulmonary disease (COPD), and tuberculosis. Mortality and hospitalization rates of these diseases were compared with those for the rest of the U.S. population and between Indian groups in the various Indian Health Service Areas. Pneumonia and influenza constitute the sixth leading cause of death among Indians and the fifth leading cause of death among the U.S. All Races population. Chronic obstructive pulmonary disease is the fourth leading cause of death among U.S. All Races, but only the tenth leading cause of death among Indians. Pneumonia and tuberculosis are more significant causes of death and disability for Indians than are COPD and cancer of the lung. The explanation for these differences in mortality rates between Indians and the general population are not known. Respiratory system diseases are responsible for 10.6% of Indian hospitalizations. The most frequent is pneumonia, which accounts for approximately 4% of all Indian hospitalizations. Differences in respiratory diseases between Indian groups are sometimes striking, with a sharp increase in mortality and hospitalization in the Areas across the northern border of the lower 48 states. There is also a much higher prevalence of cigarette smoking in those same Areas.

Mortality from infectious diseases among New Mexico's American Indians, Hispanic whites, and other whites, 1958-87

To examine ethnic differences in infectious disease-related mortality in New Mexico's American Indian, Hispanic White and other White populations, we analyzed vital records data from 1958 to 1987. We found that for most infectious causes, American Indians had the highest mortality rates, followed by Hispanics. The state's minority populations remain at increased risk for infectious disease mortality.

Injury mortality in American Indian, Hispanic, and non-Hispanic white children in New Mexico, 1958-1982

Childhood fatalities from injuries are a serious public health problem in New Mexico, a state which ranks second in the nation in injury-related mortality rates. To determine the extent of injury mortality in children in this state, and to examine time trends and differences in mortality rates in New Mexico's American Indian, Hispanic, and non-Hispanic white children aged 0-14 years, we analyzed vital records collected from 1958 to 1982. American Indian children experienced the highest mortality rates from all external causes combined. Among all three major ethnic groups, children aged 0-4 years were at the highest risk for injury fatalities. Unintentional injuries accounted for 85% of all injury-related deaths. Motor vehicle crashes and drowning were the first and second leading causes of death in all three groups, while other important causes of death included fire, choking on food or other objects, poisoning, and homicide. Although the fatality rates on most types of injuries decreased over the 25-year period, childhood fatality rates for motor vehicle crashes and homicide increased in each ethnic group. Despite the overall decrease in injury mortality rates in New Mexican children, the rates are excessively high compared to other states, especially in American Indian children.