FormalPara Key Points

  • Native Hawaiians and Pacific Islanders have elevated rates of asthma, chronic obstructive pulmonary disease (COPD), and lung cancer compared with other ethnic groups.

  • These differentials in respiratory disease are attributable in part to risk factors that are also elevated in Pacific populations, including tobacco use, stress, and obesity, and which may be offset by protective factors such as family support.

  • Promising screening and intervention approaches have been developed for Native Hawaiians and Pacific Islanders, which need to be more widely tested and disseminated in the Pacific region.

Lung cancer is the most common source of cancer mortality among Native Hawaiian and Pacific Islander (NHPI) men and the second most common among NHPI women. Moreover, compared with other ethnic groups, Native Hawaiians (NH) suffer worse cancer outcomes at a given level of cigarette smoking. To better understand the origins of these differentials, we focus on behavioral research conducted with NH in Hawai‘i, along with data from Indigenous people in Guam and the US-Affiliated Pacific Islands (USAPI). We also present research on risk and protective factors for respiratory disease and on screening and intervention approaches that have been shown to be effective in NHPI communities.

The Hawaiian Islands are relatively isolated geographically and did not experience Western contact until 1778. NH were noted by observers in the initial contacts to be robust and healthy people, but after continued Western contacts, the Indigenous population was decimated by introduced diseases and suffered economically and culturally from the loss of their native lands, religion, and language [1]. Hawai‘i was originally an independent nation until its monarch was deposed by a US-supported coup, and it was then annexed as a US territory in 1898 under protest by NH. In 1959, it received American statehood. From the mid-1800s, plantation owners imported agricultural laborers from China, Portugal, Japan, and the Philippines, who eventually became part of the local economy, and over the years, the Hawai‘i population became multiethnic, with no ethnic majority. However, despite economic development for the population as a whole, significant economic and health disparities remain for NH. A somewhat similar situation occurred in the southern Pacific Islands, which were more accessible to Western exploration and, in many cases, became British, Dutch, French, or Spanish colonies. Some eventually became independent states or US-affiliated territories; however, many remained underdeveloped economically, and at present, some do not have a level of health infrastructure comparable with the continental United States [2].

Prevalence of Respiratory Disease

Cancer registries have now been established in Hawai‘i and the USAPI (i.e., Federated States of Micronesia, Republic of the Marshall Islands, Republic of Palau, Guam, Northern Mariana Islands, and American Samoa). Lung cancer incidence and mortality data for Hawai‘i (Table 40.1a) show marked elevation in NH (both genders) compared with other ethnicities in Hawai‘i.

Table 40.1a Lung cancer incidence and mortality (per 100,000 per annum) in Hawai‘i adults by ethnicity and gender, 2014–2018 [3]
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Data for the territory of Guam (Table 40.1b) show that the overall rate of lung cancer is particularly elevated for Chamorros, the Indigenous people of that region. Lung cancer is also elevated for Micronesians who have immigrated to Guam from other USAPI. Lung cancer accounts for 28% of all cancer deaths in Guam and is the leading cause of cancer-related mortality. These elevated rates can be linked to the fact that Guam is largely urban (95%) and its military installations may expose residents to air pollution, particularly diesel exhaust.

Table 40.1b Lung cancer incidence and mortality (per 100,000 per annum) in Guam adults by ethnicity, 2013–2017 (Micro = Micronesian) [4]
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Separate tabulations for three states within the Federated States of Micronesia (Table 40.1c) show that lung cancer rates are relatively low for Chuuk and Pohnpei but are elevated in Yap, which has been suggested as being linked to a higher rate of cigarette smoking on the island.

Table 40.1c Lung cancer prevalence (per 100,000 per annum) for Central Pacific adults, by state, 2007–2020. Data are for adjusted prevalence, standardized to the US population (Rep = republic; RMI = Republic of the Marshall Islands; FSM = Federated States of Micronesia) [5]
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Importantly, NH also have elevated rates for other respiratory diseases. Data from the Behavioral Risk Factor Surveillance System (BRFSS) in Hawai’i [6] show NH particularly elevated for the prevalence of asthma and COPD compared with Asian Americans (Japanese and Chinese), Filipinos, and Whites. This differential is relevant for lung cancer because longitudinal studies have shown asthma to predict the development of COPD, and ~1% of COPD patients develop lung cancer annually [7]. Thus, ethnic differentials in the prevalence of asthma and COPD may be significant for understanding differentials in lung cancer.

Risk Factors

Several behavioral factors are related to the risk of lung cancer. Cigarette smoking is a major pathway, and other factors can produce risk or protection independent of smoking. Ethnic differences in levels of these risk and protective factors may help account for differentials in the rates of lung disease.

Cigarette Smoking and Other Primary Carcinogens

Cigarette smoking is a major risk factor for lung cancer. Secondhand smoke exposure (at home or worksite), asbestos, air pollution, genetic mutations, and radiation from either manufactured or natural sources (e.g., radon) are also established risk factors. These factors represent a more direct disease process because they involve exposure to primary carcinogens.

Social Determinants

The probability of exposure to one or more cancer-risk factors can be derived in part from social determinants. Specifically, the rates of onset and progression for various diseases are related to lower socioeconomic status (SES) (i.e., income, education, and occupational status), job and food insecurity, and social isolation. SES differentials have been documented across a variety of Western and Asian countries [8], and similar findings have been demonstrated in USAPI populations [2]. Social determinants are presumed to represent a more indirect risk process because they influence the likelihood of exposure to primary carcinogens.

Pleasants et al. reported that the likelihood of developing COPD is related to several SES indices, being ~14 times higher for the lowest socioeconomic groups than for the highest [8]. Notably, these effects occur within a matrix of exposures because lower-SES populations are more likely to live in poverty, smoke, be exposed to secondhand smoke and air pollution, and have less access to healthcare. Our own research in Hawai‘i has demonstrated that NH are more likely to smoke and be exposed to secondhand smoke, both factors elevating their risk for respiratory disease [9].

Life Stress

A long-standing body of research has linked stress from negative life events to adverse health outcomes. Considering the particular circumstances of Native Hawaiians, researchers have studied the effects on NH of historical trauma derived from historical events including the loss of native lands, religion, and language. Though occurring in the past, these can have an impact in the present through discrimination and false or reconstructed narratives, communicated across generations. Research has shown the salience of historical trauma for cigarette smoking among NH students [10]. Stress also derives from insecurity regarding current life circumstances, such as financial insecurity from low income and unstable employment, which has been related to risk for respiratory disease among NH [9]. Food insecurity is a specific source of stress for NH. Whether stress contributes to lung cancer risk indirectly, by affecting the likelihood of cigarette smoking, or directly, by influencing rates of cancer progression, is not settled at this time, but recent reviews provide support for both possibilities.

Obesity

Obesity has been linked to respiratory disorders among Hawai‘i adolescents and adults. Recent data show that NH (compared to Asians) have a higher rate of overweight status, and this is related to both asthma and COPD [9]. The link between obesity and lung cancer has been debated among epidemiologists, but recent analyses have linked lung cancer specifically to central adiposity (i.e., stomach fat). Because obesity is more prevalent among lower-SES persons (at least in higher-income countries), this establishes obesity within the matrix of social determinants of health for this Indigenous population.

Protective Factors and Interventions

Social Support

Emotional support (e.g., confiding and acceptance) and/or instrumental support from family members (e.g., assistance with finances or household tasks) is a well-established protective factor across a range of health conditions. Data from Hawai‘i school studies indicate that NH youths who report a high level of support from parents show reduced health-risk behaviors, including cigarette smoking [11]. Moreover, family support helps buffer (i.e., reduce) the effect of life stress on health-risk behavior. For example, our data from a study of Hawai‘i high-school students show that the impact of life stress on smoking and other substance use is reduced among teens with a higher level of parental support [11]. In the long run, reducing cigarette smoking will have a significant impact on the likelihood of being afflicted with lung cancer.

Cancer Screening

Cancer screening programs are often problematic for Pacific Island populations, where access to medical personnel and sophisticated diagnostic equipment can be limited [2]. Accordingly, alternative approaches that address logistical and cultural barriers to screening have been developed. For example, a study conducted in Yap showed that urine self-sampling for cervical cancer screening is more feasible than clinician-collected cytology sampling [12]. Computed tomography (CT) screening allows lung cancer to be diagnosed early, addressing a particular issue in Pacific Island populations where cancer is often diagnosed in its later stages. While CT screening is less available in many of the USAPI, BRFSS data from Hawai‘i adult smokers revealed that the proportion of NH receiving CT scans as a screening procedure ranged from 10.2% (2019) to 18.3% (2021), higher than the screening rates for Japanese and White adult smokers (9–12%) [6]. This positive disparity has been attributed to outreach efforts conducted in Native Hawaiian communities.

Interventions

Although there are limited data on lung cancer screening interventions in Hawai‘i and Guam, several studies have illustrated effective approaches for various types of interventions in Pacific populations. Guiding principles for these interventions are that they must be culturally appropriate, utilize a broad-reaching public health model, and, where possible, be conducted by trained Indigenous personnel. We present three examples of such interventions.

Culturally Appropriate Physical Exercise

Cardiometabolic disease is an issue for NH, and physical exercise can help counter the risks derived from obesity and high blood pressure. Kaholokula et al. conducted an intervention for NH at risk from high systolic blood pressure; this involved recruiting adults from community settings and providing training in hula, which has long been a popular and important part of Hawaiian culture [13]. An intervention group received basic medical education and then participated in a 12-week series of lessons taught by a kumu hula (cultural practitioner). A wait-list control group initially received the educational component only. After all assessments were complete, participants in the control group were then invited to receive hula sessions.

The intervention group showed a significant decrease in risk for heart disease, while the control group showed some decrease in risk status (probably due to the educational component) but less than the intervention group. This study demonstrated the effectiveness of a culturally appropriate exercise intervention for NH, providing an empirically validated model that can be used by other populations.

Smoking Prevention in Guam Adolescents

Pallav Pokhrel and colleagues developed a culturally grounded, school-based curriculum to prevent cigarette smoking and betel nut chewing. The curriculum was developed through formative research conducted to understand the high rates of tobacco product and betel nut use observed among Guam adolescents [14]. The curriculum was implemented with middle-school students and focused on teaching students about the health risks of cigarette smoking and betel nut chewing; importantly, the intervention included training adolescents to resist the social influences that encourage the use of these products. Videos helped adolescents formulate and practice realistic and culturally appropriate strategies for resisting pressures to smoke or use betel nuts. A randomized controlled trial of the curriculum was recently completed in eight public middle schools in Guam, four of which received the curriculum and four served as controls. Evaluation data showed that at three-month follow-up, those who received the curriculum were likely to be less open to using e-cigarettes in the future.

Increasing Pacific Islander Participation in Clinical Trials

Kevin Cassel and colleagues used their experience with building research infrastructure for colon cancer screening in American Samoa to design an intervention to increase participation by Pacific Islander women in the Tomographic Mammographic Imaging Screening Trial. Their approach utilized health educators from Micronesian backgrounds, who were trained to provide educational sessions with Pacific Islander women in community health centers. Across-time comparisons showed that the intervention increased clinical trial participation by Pacific Islander women from 2% at baseline to 20% at follow-up, exceeding the targeted effect [15].

Conclusions

In this chapter, we have outlined data on the prevalence of lung cancer among Pacific populations, identified cancer risk factors and protective factors, and discussed cancer screening approaches that can be useful among NHPI populations. Risk factors for lung cancer tend to occur within a matrix of social factors under the rubric of SES, and SES may have effects independent of ethnicity. Based on our research with NH, we have proposed a conceptual model of the direct and indirect links between ethnicity and lung cancer (Fig. 40.1). The model recognizes that while ethnicity carries risk, the risk is partly transmitted through intermediate behavioral factors such as a higher rate of cigarette smoking. The model also recognizes that ethnicity may have protective effects (e.g., through stronger family support).

Fig. 40.1
A conceptual model depicts genetics having a positive association with lung cancer. Ethnicity leads to smoking, leading to C O P D, which leads to lung cancer. Social support and screening have an inverse association with lung cancer. Low S E S has a positive association with smoking.

Conceptual model of direct and indirect links between ethnicity and lung cancer. (+ indicates positive association; − indicates inverse association; solid lines indicate indirect pathways from ethnicity to lung cancer through cigarette smoking and COPD; dotted lines indicate indirect pathways from ethnicity to lung cancer through social support. Genetics and CT screening are hypothesized to have direct effects (in opposite directions) to the likelihood of lung cancer)

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We have also emphasized that while genetic factors may be relevant, lung cancer is related to respiratory diseases such as asthma and COPD, which begin earlier than the typical onset of cancer. The overall implication is that while screening for lung cancer can reduce cancer mortality among adult smokers, lung cancer prevention requires comprehensive efforts, which include smoking prevention programs in schools and screening for early signs of respiratory disease (e.g., chronic bronchitis) in young adulthood.