IMPORTANCE

Interactions between race and county-level factors associated with mortality, such as employment, education, income, and population density, are understudied among Asian American and Pacific Islander populations.

OBJECTIVE

To compare all-cause, cancer, and heart disease mortality rates between Pacific Islander and Asian American adults across county-level factors.

DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study examined National Center for Health Statistics death certificate data on non-Hispanic Asian American and Pacific Islander adults (aged 20-84 years) between January 1, 2018, and December 31, 2020. County-level socioeconomic data were obtained from the American Community Survey, and population density was determined using Rural-Urban Continuum Codes. Analyses were conducted between August 1, 2023, and September 4, 2024.

EXPOSURES

County-level unemployment, educational attainment, median household income, and population density.

MAIN OUTCOMES AND MEASURES

Age-standardized all-cause, cancer, and heart disease mortality rates and mortality rate ratios (MRRs), comparing Pacific Islander with Asian American individuals by sex and age. Interactions between race and county-level factors associated with MRRs were evaluated using P value for trend across county-level factors.

RESULTS

During 2018 to 2020, 43 221 696 Asian American and 1 281 221 Pacific Islander adults resided in the US. A total of 148 939 Asian American individuals (16.7% aged 20-54 years, 17.2% aged 55-64 years, and 66.1% aged ≥65 years; 57.5% male) and 9628 Pacific Islander individuals (29.9% aged 20-54 years, 23.0% aged 55-64 years, and 47.1% aged ≥65 years; 57.2% male) died of any cause. Across all county-level factors, Pacific Islander adults had elevated all-cause, cancer, and heart disease mortality rates compared with Asian American adults (female: MRR range from 1.82 [95% CI, 1.67-1.98] for population <250 000 to 2.93 [95% CI, 2.73-3.14] for lowest unemployment tertile; male: MRR range from 1.64 [95% CI, 1.50-1.78] for lowest income tertile to 2.47 [95% CI, 2.31-2.63] for lowest unemployment tertile). Across all county-level factors, the largest relative all-cause mortality differences between Pacific Islander and Asian American adults occurred in counties with the lowest unemployment (female: MRR, 2.93 [95% CI, 2.73-3.14]; male: MRR, 2.47 [95% CI, 2.31-2.63]), highest educational attainment (female: MRR, 2.71 [95% CI, 2.53-2.90]; male: MRR, 2.39 [95% CI, 2.25-2.54]), highest median household income (female: MRR, 2.67 [95% CI, 2.56-2.79]; male: MRR, 2.25 [95% CI, 2.17-2.33]), and highest population density (female: MRR, 2.79 [95% CI, 2.67-2.92]; male: MRR, 2.37 [95% CI, 2.28-2.47]). No trends in relative cancer mortality differences between Pacific Islander and Asian American adults across county-level factors were observed overall except for greater population density among women (<250 000 population: MRR, 1.49 [95% CI, 1.25-1.76; >1 000 000 population, 2.13 [95% CI, 1.95-2.32]). The largest heart disease MRRs for Pacific Islander compared with Asian American individuals occurred among those younger than 65 years, with the greatest relative mortality among those aged 20 to 54 years in counties with the lowest unemployment (female: MRR, 14.21 [95% CI, 9.89-20.04]; male: MRR, 5.75 [95% CI, 4.58-7.15]) and highest educational attainment (female: MRR, 13.69 [95% CI, 9.68-18.94]; male: MRR, 6.17 [95% CI, 5.00-7.54]), median household income (female: MRR, 11.97 [95% CI, 9.55-14.91]; male: MRR, 5.16 [95% CI, 4.49-5.91]), and population density (female: MRR, 11.77 [95% CI, 9.39-14.62]; male: MRR, 5.48 [95% CI, 4.76-6.29]).

CONCLUSIONS AND RELEVANCE

In this cross-sectional study, all-cause mortality disparities between Asian American and Pacific Islander populations worsened in counties with higher socioeconomic status and greater population density. Historical aggregation of Pacific Islander with Asian American individuals may have misled health improvement efforts, especially for Pacific Islander adults who lived in high socioeconomic and more populated areas.