To compare the incident exposure design with the prevalent exposure design in cohort studies, to systematically evaluate the performance of different analytical methods within the incident exposure design framework, using the association between hypertension and cardiovascular disease as an example.
Based on the UK Biobank cohort, we selected an elderly population aged 60-65 years at baseline. Both prevalent exposure and incident exposure designs (time-window fixed grouping, time-zero random assignment, time-zero distribution matching, and time-dependent variable) were applied to assess the association between hypertension and incident cardiovascular disease.
Using the time-dependent variable as reference [hazard ratio (HR)=1.77, 95% confidence interval (CI): 1.68-1.88], the prevalent exposure design underestimated the effect size by 23% (HR=1.36) due to selection bias. The time-window fixed grouping introduced immortal time bias, leading to an 11% underestimation (HR=1.57). The time-zero random assignment and time-zero distribution matching, by defining a valid time-zero, partially controlled for bias, yielding HRs of 1.63 and 1.66, respectively. However, some degree of underestimation persisted.
The prevalent exposure design may systematically underestimate long-term disease risk. The event-based incident exposure design is recommended, particularly the time-dependent variable method which effectively controls for bias, to provide more reliable evidence for assessing the risk of incident cardiovascular disease associated with hypertension in elderly adults.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |