Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Quebec, Canada.
Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada.
Int J Epidemiol. 2024 Oct 13;53(6). doi: 10.1093/ije/dyae135.
Despite poor agreement, neighbourhood income is used as a proxy for household income, due to a lack of data availability. We quantified misclassification between household and neighbourhood income and demonstrate quantitative bias analysis (QBA) in scenarios where only neighbourhood income is available in assessing income inequalities on colorectal cancer mortality.
This was a retrospective study of adults with colorectal cancer diagnosed 2006-14 from Statistics Canada's Canadian Census Health and Environment Cohort. Neighbourhood income quintiles from Statistics Canada were used. Census household income quintiles were used to determine bias parameters and confirm results of the QBA. We calculated positive and negative predictive values using multinomial models, adjusting for age, sex and rural residence. Probabilistic QBA was conducted to explore the implication of exposure misclassification when estimating the effect of income on 5-year mortality.
We found poor agreement between neighbourhood and household income: positive predictive values ranged from 21% to 37%. The bias-adjusted risk of neighbourhood income on 5-year mortality was similar to the risk of mortality by household income. The bias-adjusted relative risk of the lowest income quintile compared with the highest was 1.42 [95% simulation interval (SI) 1.32-1.53] compared with 1.46 [95% confidence interval (CI) 1.39-1.54] for household income and 1.18 (95% CI 1.12-1.24) for neighbourhood income.
QBA can be used to estimate adjusted effects of neighbourhood income on mortality which represent household income. The predictive values from our study can be applied to similar cohorts with only neighbourhood income to estimate the effects of household income on cancer mortality.
由于数据可用性不足，尽管一致性较差，但仍将社区收入用作家庭收入的替代指标。我们量化了家庭收入和社区收入之间的分类错误，并在仅可用社区收入评估结直肠癌死亡率的收入不平等的情况下展示了定量偏差分析（QBA）。
这是一项对 2006-14 年期间被诊断患有结直肠癌的加拿大普查健康与环境队列中成年人的回顾性研究。使用了来自加拿大统计局的社区收入五分位数。使用人口普查家庭收入五分位数来确定偏差参数并确认 QBA 的结果。我们使用多项模型调整年龄、性别和农村居住状况来计算阳性和阴性预测值。进行了概率 QBA，以探索在估计收入对 5 年死亡率的影响时暴露分类错误的含义。
我们发现社区收入和家庭收入之间的一致性较差：阳性预测值的范围为 21%至 37%。经过偏差调整的社区收入对 5 年死亡率的风险与家庭收入的死亡率风险相似。与家庭收入相比，最低五分位数的收入与最高五分位数的收入的偏差调整相对风险为 1.42[95%模拟区间（SI）1.32-1.53]，而家庭收入为 1.46[95%置信区间（CI）1.39-1.54]，而社区收入为 1.18（95%CI 1.12-1.24）。
QBA 可用于估计代表家庭收入的社区收入对死亡率的调整效果。我们研究中的预测值可应用于仅有社区收入的类似队列，以估计家庭收入对癌症死亡率的影响。
