Baseline characteristics by allocation
| Active (n=137) | Control (n=103) | |
|---|---|---|
| Participant characteristics | ||
| Type of participant | ||
| Resident, n (%) | 115 (84%) | 79 (77%) |
| Carer, n (%) | 22 (16%) | 24 (23%) |
| Age, years | ||
| Mean (SD) | 67.5 (12.8) | 66.6 (13.4) |
| Sex | ||
| Male, n (%) | 51 (37%) | 31 (30%) |
| Female, n (%) | 86 (63%) | 72 (70%) |
| Ethnicity | ||
| Asian/Asian British, n (%) | 5 (4%) | 6 (6%) |
| African/Afro–Caribbean, n (%) | 17 (12%) | 24 (24%) |
| White, n (%) | 110 (80%) | 71 (69%) |
| Mixed, n (%) | 2 (1%)* | 1 (1%)† |
| Chinese, n (%) | 2 (1%) | 1 (1%) |
| Other, n (%) | 1 (1%)‡ | 0 (0%) |
| Occupational class | ||
| 1 (Managerial, administrative and professional occupations), n (%) | 53 (39%) | 55 (53%) |
| 2 (Intermediate occupations), n (%) | 18 (13%) | 10 (10%) |
| 3 (Small employers and own-account workers), n (%) | 9 (7%) | 3 (3%) |
| 4 (Lower supervisory and technical occupations), n (%) | 18 (13%) | 12 (12%) |
| 5 (Semiroutine and routine occupations), n (%) | 39 (28%) | 20 (19%) |
| Never/long-term (>5 years) unemployed, n (%) | 0 (0%) | 3 (3%) |
| Body mass index, kg/m2 | ||
| Mean (SD) | 29.5 (6.3) | 29.0 (5.9) |
| Smoking status | ||
| Current smoker, n (%) | 26 (19%) | 17 (17%) |
| Non-smoker, n (%) | 111 (81%) | 86 (83%) |
| Vaccination history | ||
| Seasonal flu vaccine in the year preceding enrolment, n (%) | 88 (64%) | 72 (70%) |
| Pneumococcal vaccine in 5 years preceding enrolment, n (%) | 56 (41%) | 35 (34%) |
| Biochemical parameters | ||
| Mean serum 25(OH)D, nmol/L (SD) | 42.4 (23.4) | 43.6 (22.6) |
| Serum 25(OH)D<25 nmol/L, n (%) | 36 (26%) | 24 (23%) |
| Serum 25(OH)D 25–49 nmol/L, n (%) | 55 (40%) | 38 (37%) |
| Serum 25(OH)D 50–74 nmol/L, n (%) | 32 (23%) | 35 (34%) |
| Serum 25(OH)D≥75 nmol/L, n (%) | 14 (10%) | 6 (6%) |
| Mean serum corrected calcium, mmol/L (SD) | 2.24 (0.10) | 2.24 (0.09) |
| Unit characteristics | ||
| Level of care | ||
| <24 h care, n (%) | 133 (97%) | 96 (93%) |
| 24 h care, n (%) | 4 (3%) | 7 (7%) |
| Number of residents | ||
| <30, n (%) | 42 (31%) | 31 (30%) |
| ≥30, n (%) | 95 (69%) | 72 (70%) |
| Month of randomisation | ||
| November–April, n (%) | 92 (67%) | 66 (64%) |
| May–October, n (%) | 45 (33%) | 37 (36%) |
*One mixed white/Asian origin, one mixed Filipino/Spanish origin.
†Mixed black African/white origin.
‡Venezuelan.
25(OH)D, 25-hydroxyvitamin D.