UC Davis

Armenians, a growing ethnic minority population in the United States, have historically faced war, economic instability, and persecution including the Armenian Genocide in the early 20th century. In search of refuge, many Armenians relocated to the United States and over time, California has become the state with the largest population of Armenians. However, research on the population is limited due to the lack of accurate Armenian population estimates, a standardized collection of Armenian ethnicity or an Armenian surname list. Consequently, many Armenians are included in the ‘White’ or ‘Some Other Race’ race/ethnicity categories in research studies despite possible differences in genetic and sociodemographic factors affecting health patterns, including cancer incidence and survival. As cancer patterns specifically among Armenians in California have remained unknown, the overall purpose of this dissertation was to fill this research gap by constructing an Armenian Surname List (ASL) and using the ASL to identify and compare cancer incidence, stage at diagnosis and survival between Armenian and non-Hispanic White (NHW) patients in California. In the first chapter, we extracted Armenian surnames from the Middle Eastern Surname List and constructed the ASL using California death records from 1905 to 2020. We used NamSor, an onomastic classification tool, to evaluate the ASL by ranking surname country of origin. In the second chapter, we used the ASL and CCR birthplace information to identify Armenians with cancer and American Community Survey data to identify the Armenian population in California. We then selected 10 most common cancers among Armenian males and females and calculated age-adjusted and sex stratified proportional incidence ratios (PIR) and incidence rate ratios (IRR) compared with NHW patients. In the third and final chapter, we used the ASL and birthplace information in the CCR to compare late-stage at diagnosis and cause-specific cancer survival for four tobacco-related cancers (stomach, lung, colorectal, and bladder) between Armenian and NHW patients. We used Cox proportional hazards models to calculate cancer-specific survival and logistic regression models to calculate odds of late-stage diagnoses. In the first chapter, we constructed and evaluated the ASL and found that 81% of the 3,428 unique surnames in the ASL had Armenia as the most or second-most likely country of origin. In the second chapter, we identified Armenians (n=27,212) diagnosed with common cancers in California and found significant differences in cancer incidence compared to NHW patients. Among Armenian males, the 10 most frequent cancers were prostate, lung, colorectal, bladder, non-Hodgkin lymphoma (NHL), stomach, leukemia, kidney, pancreas, and liver and intrahepatic bile duct (IBD). Among Armenian females, the 10 most frequent cancers were breast, colorectal, lung, uterine, NHL, thyroid, ovary, stomach, pancreas, and leukemia. Among the 10 most frequent cancers, Armenian males had higher proportions of seven cancers including stomach (PIR=2.39, 95% CI=2.19-2.60), bladder (PIR=1.53, 95% CI=1.45-1.61), colorectal (PIR=1.29, 95% CI=1.23-1.35), lung (PIR=1.16, 95% CI=1.11-1.21), leukemia (PIR=1.16, 95% CI=1.06-1.26), liver and IBD (PIR=1.19, 95% CI=1.05-1.34), and kidney (PIR=1.11, 95% CI=1.01-1.21) cancers. Armenian females also had higher proportions of seven cancers including stomach (PIR=3.24, 95% CI=2.93-3.57), thyroid (PIR=1.47, 95% CI=1.36-1.60), colorectal (PIR=1.29, 95% CI=1.23-1.35), pancreatic (PIR=1.20, 95% CI=1.09-1.33), leukemia (PIR=1.20, 95% CI=1.08-1.32), NHL (PIR=1.15, 95% CI=1.05-1.24), and ovarian (PIR=1.14, 95% CI=1.04-1.24) cancers. Exploratory IRR analyses showed higher stomach (IRR=1.78, 95% CI=1.55-2.06), bladder (IRR=1.13, 95% CI=1.05-1.23), and colorectal (IRR=1.12, 95% CI=1.03-1.20) cancers among Armenian males and higher stomach (IRR=2.54, 95% CI=2.15-2.99) cancer among Armenian females. In the third chapter, we found higher odds of late-stage colorectal (OR=1.12, 95% CI=1.03-1.22), lung (OR=1.26, 95% CI=1.12-1.42), and stomach (OR=1.43, 95% CI=1.17-1.74) cancers diagnosed among Armenian patients compared to NHW patients, and a moderate survival advantage of Armenian patients for stomach (HR=0.85, 95% CI=0.76-0.94), lung (HR=0.86, 95% CI=0.82-0.91), colorectal (HR=0.82, 95% CI=0.77-0.88), and bladder (HR=0.87, 95% CI=0.76-0.99) cancers. Among Armenian patients, we found that lower neighborhood socioeconomic status was associated with late-stage stomach and bladder cancer diagnoses, and public health insurance was associated with late-stage lung, colorectal, and bladder cancer diagnoses. This dissertation project is the first to create an Armenian surname list, the ASL, that can be used to identify Armenians in databases for epidemiological research and in other research fields concerning Armenian populations. With the use of the ASL and CCR, we found that Armenian patients had higher incidence of several common cancers, which may relate to risk factors including tobacco-use, obesity, and exposure to harmful environmental agents. Our findings of a higher risk for late-stage diagnoses of numerous tobacco-related cancers compared to NHW patients, and that Armenian patients with lower socioeconomic status and public health insurance had higher likelihood of late-stage diagnoses, reveal a need for increased access to reliable health care and cancer screening. Our findings also show the need for further research to address risk factors associated with specific cancers among Armenians and to understand factors associated with the modest survival advantage observed among the Armenian patients compared to NHW patients. Overall, this dissertation provides a new identification tool and data to inform evidence-based cancer control efforts for the growing Armenian population in California.