Table 2.
Adjusted hazard ratios of COVID-19 risk and severity according to healthful plant-based dietary index scores.
| Low hPDI (Q1; n=148,143) | Intermediate hPDI (Q2-Q3; n=296,286) | High hPDI (Q4; n=148,142) | P for trend | |
|---|---|---|---|---|
|
|
||||
| hPDI score, median (P25-P75) | 45 (43–47) | 51 (49–52) | 56 (55–58) | |
| COVID-19 risk | ||||
| No. of events/person-months | 8,739 / 839,747 | 15,733 / 2,026,824 | 7,359 / 1,022,078 | — |
| Incidence rate (10,000 person-months; 95% CI) | 104.1 (101.9–106.2) | 77.6 (76.4–78.8) | 72.0 (70.4–73.7) | — |
| Age-adjusted model | 1.00 (Ref) | 0.85 (0.82–0.87) | 0.80 (0.78–0.83) | <0.001 |
| Multivariable model 2 | 1.00 (Ref) | 0.85 (0.83–0.87) | 0.81 (0.78–0.83) | <0.001 |
| Multivariable model 3 | 1.00 (Ref) | 0.91 (0.89–0.93) | 0.91 (0.88–0.94) | <0.001 |
| COVID-19 risk (positive test) | ||||
| No. of events/person-months | 1,423 / 869,664 | 2,829 / 2,081,970 | 1,350 / 1,046,887 | — |
| Incidence rate (10,000 person-months; 95% CI) | 16.4 (15.5–17.2) | 13.6 (13.1–14.1) | 12.9 (12.2–13.6) | — |
| Age-adjusted model$ | 1.00 (Ref) | 0.86 (0.83–0.90) | 0.79 (0.75–0.83) | <0.001 |
| Multivariable model 2$ | 1.00 (Ref) | 0.87 (0.84–0.91) | 0.80 (0.76–0.84) | <0.001 |
| Multivariable model 3$ | 1.00 (Ref) | 0.88 (0.85–0.92) | 0.82 (0.78–0.86) | <0.001 |
| Severe COVID-19 | ||||
| No. of events/person-months | 187 / 871,995 | 390 / 2,086,790 | 163 / 1,049,476 | — |
| Incidence rate (10,000 person-months; 95% CI) | 2.1 (1.9–2.5) | 1.9 (1.7–2.1) | 1.6 (1.3–1.8) | — |
| Age-adjusted model | 1.00 (Ref) | 0.66 (0.56–0.77) | 0.45 (0.36–0.57) | <0.001 |
| Multivariable model 2 | 1.00 (Ref) | 0.66 (0.57–0.78) | 0.45 (0.36–0.57) | <0.001 |
| Multivariable model 3 | 1.00 (Ref) | 0.77 (0.66–0.91) | 0.59 (0.47–0.74) | <0.001 |
Hazards ratios and 95% CI for COVID-19 risk and severity. COVID-19 risk defined using a validated symptom-based model. COVID-19 or a RT-PCR positive test report. COVID-19 severity was defined based on hospitalization with requirement of oxygen support (methods, supplement).
Cox proportional hazards models were stratified by calendar date at study entry, country of origin, and 10-year age group (Age-adjusted model).
Multivariable model 2 was further adjusted for sex (male, female), race/ethnicity (White, Black, Asian, Other), index of multiple deprivation (most deprived <3, intermediate deprived 3 to 7, less deprived >7), population density (<500 individuals/km2, 500 to 1,999 individuals/km2, 2,000 to 4,999 individuals/km2, and ≥5,000 individuals/km2), and healthcare worker status (yes with interaction with COVID-19 patients, yes without interaction with COVID-19 patients, no).
Model 3 was further adjusted for presence of comorbidities [diabetes (yes, no), cardiovascular disease (yes, no), lung disease (yes, no), cancer (yes, no), kidney disease (yes, no)], body mass index (<18.5 kg/m2, 18.5 to 24.9 kg/m2, 25.0 to 29.9 kg/m2, and ≥30 kg/m2), smoking status (yes, no), and physical activity (<1 day/week, 1 to 2 days/week, 3 to 4 days/week, ≥5 days/week).
Inverse probability-weighted analyses were conducted to account for predictors of obtaining RT-PCR testing (presence of COVID-19-related symptoms, interaction with a COVID-19 case, healthcare worker, age group, and race). inverse probability-weighted Cox proportional hazards models were stratified by 10-year age group and date with additional adjustment for the covariates used in previous models.