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PMC full text:
Gut. Author manuscript; available in PMC 2022 Nov 1.
Published in final edited form as:
Gut. 2021 Nov; 70(11): 2096–2104.
Published online 2021 Sep 6. doi: 10.1136/gutjnl-2021-325353

Table 1.

Baseline characteristics of study participants according to categories of the diet quality score

All participants (n=592,571)Low hPDI (Q1; n=148,143)Intermediate hPDI (Q2-Q3; n=296,286)High hPDI (Q4; n=148,142)

hPDI score, median [P25-P75]50 (47 to 54)45 (43–47)51 (49–52)56 (55–58)
Demographic characteristics

Age, years56 (44–65)52 (41–62)57 (45–66)57 (45–65)
 ≥18–2414,397 (2.4)5,146 (3.4)5,846 (2.0)3,405 (2.3)
 25–3452,922 (8.9)16,535 (11.2)23,150 (7.8)13,237 (8.9)
 35–4486,251 (14.6)26,907 (18.2)40,145 (13.5)19,199 (13.0)
 45–54125,802 (21.2)34,890 (23.6)62,491 (21.1)28,421 (19.2)
 55–64158,637 (26.8)34,279 (23.1)81,837 (27.6)42,521 (28.7)
 ≥65153,810 (26.0)30,215 (20.4)82,413 (27.8)41,182 (27.8)
 Missing752 (0.1)171 (0.1)404 (0.1)177 (0.1)
Sex, No. (%)
 Male187,450 (31.6)58,199 (39.3)93,162 (31.4)36,089 (24.4)
 Female404,126 (68.2)89,706 (60.5)202,605 (68.4)111,815 (75.5)
 Prefer not to say995 (0.2)238 (0.2)519 (0.2)238 (0.2)
Raceε, No. (%),
 White568,770 (96.0)141,365 (95.4)284,804 (96.1)142,601 (96.3)
 Black4,328 (0.7)1,466 (1.0)2,053 (0.7)809 (0.5)
 Asian10,435 (1.8)2,954 (1.9)5,043 (1.7)2,438 (1.6)
 Other7,228 (1.2)1,925 (1.3)3,463 (1.2)1,840 (1.2)
 Missing1,810 (0.3)433 (0.3)923 (0.3)454 (0.3)
Country, No. (%)
 UK543,984 (91.8)135,360 (91.4)272,494 (92.0)136,130 (91.9)
 US48,587 (8.2)12,783 (8.6)23,792 (8.0)12,012 (8.1)
Index of deprivation, No. (%)
 Most deprived, decile 11,3416 (2.3)4,696 (3.1)6,163 (2.1)2,557 (1.7)
 Least deprived, decile 10103,608 (17.5)23,122 (15.6)53,652 (18.1)26,834 (18.1)
 Missing40,759 (6.9)10,489 (7.1)20,249 (6.8)10,021 (6.8)
Population density, km2, No. (%)
 <500119,782 (20.2)28,139 (19.0)61,230 (20.7)30,413 (20.5)
 500–1,99990,541 (15.3)23,631 (16.0)45,902 (15.5)21,008 (14.2)
 2,000 4,99994,345 (15.9)24,813 (16.7)47,233 (15.9)22,299 (15.1)
 ≥5,000244,295 (41.2)60,156 (40.6)120,319 (40.6)63,820 (43.1)
 Missing43,608 (7.4)11,404 (7.7)21,602 (7.3)10,602 (7.2)
Healthcare worker, yes, No. (%)41,141 (6.9)10,633 (2.3)20,183 (6.8)10,325 (7.0)

Lifestyle characteristics

Smoking status, No (%)
 Never475,347 (81.9)113,165 (79.0)238,192 (81.9)123,990 (84.6)
 Former87,901 (15.1)22,683 (15.8)44,771 (15.4)20,447 (13.9)
 Current17,401 (3.0)7,402 (5.2)7,837 (2.6)2,162 (1.5)
Physical activity
 < 1 day/week106,294 (17.9)37,258 (25.2)50,713 (17.1)18,323 (12.4)
 1–2 days/week224,606 (37.9)59,325 (40.0)113,749 (38.4)51,532 (34.8)
 3–4 days/week143,548 (24.2)30,009 (20.3)73,601 (24.8)39,938 (27.0)
 ≥ 5 days/week117,007 (19.7)21,164 (14.3)57,701 (19.5)38,142 (25.7)
 Missing1,116 (0.2)387 (0.3)522 (0.2)207 (0.1)
Body mass index, Kg/m225.1 (22.6–28.7)26.6 (23.6–30.7)25.2 (22.7–28.524.0 (21.8–26.9)
 <18.512,004 (2.0)2,680 (1.8)5,540 (1.9)3,784 (2.6)
 18.5–24.9277,536 (46.8)52,109 (35.2)138,503 (46.7)86,924 (58.7)
 25–29.9189,197 (31.9)51,517 (34.8)97,919 (33.0)39,761 (26.8)
≥30113,056 (19.1)41,655 (28.1)53,909 (18.2)17,492 (11.8)
 Missing778 (0.1)182 (0.1)415 (0.1)181 (0.1)
Mask wearing, No (%)
 Most of the time / always437,782 (73.9)113,202 (76.4)218,402 (73.7)106,178 (71.6)
 Never / sometimes152,551 (25.7)34,240 (23.1)76,809 (25.9)41,502 (28.0)
 Missing2,238 (0.4)701 (0.5)1,075 (0.4)462 (0.3)

Clinical history, yes, No. (%)

Diabetes20,058 (3.4)6,079 (4.1)10,158 (3.4)3,821 (2.6)
Heart disease20,376 (3.4)5,200 (3.5)10,660 (3.6)4,516 (3.0)
Cancer6,559 (1.9)1,643 (1.8)3,348 (1.9)1,568 (1.8)
Lung disease62,999 (10.6)17,534 (11.8)31,227 (10.5)14,238 (9.6)
Kidney disease5,134 (0.9)1,492 (1.0)2,594 (0.9)1,048 (0.7)

Values are median (P25-P75) for continuous variables; numbers and (percentages) for categorical variables.

εRace was self-reported by the participants.
Index of deprivation and population density were generated using zipcode or postcode information linked with census track data. Country-specific deprivation indices were generated (supplement).
Mask wearing information was collapsed into two categories: participants who wore masks ‘none of the time or sometimes’, and those who reported wearing masks ‘most of time/ always’.
*hPDI ranges from 0 to 70, with higher scores indicating higher adherence to a healthy plant-based diet.