NSHD: response to dietary measures
The majority of participants who responded to the diet diaries at each age (see the table below) completed the full five days (83-99%).
Up to 1999, the majority of diet diaries were completed in summer and autumn (68-94%) and excluding winter (<5%) when shortages of fresh fruit and vegetables would have been most apparent.
In 2006-2011, diet diaries were completed equally throughout all four seasons (20-28%).
Response to dietary measures in NSHD
The original NSHD cohort consisted of 5,362 participants.
| Year | Age (y) | N interviewed | Response to diet question (n(%)) | Diet Diary ≥3 days†‡ |
|---|---|---|---|---|
| 1950 | 4 | 4,711 | 4,599 (98%) | N/A |
| 1982 | 36 | 3,322 | 2,428 (73%)** | 2,411 |
| 1989 | 43 | 3,262 | 2,280 (70%)** | 2,256 |
| 1999 | 53 | 3,035 | 1,776 (59%)** | 1,772 |
| 2006-2010 | 60-64 | 2,662 | 1,893 (71%)** | 1,869 |
| 2014-2016 | 68-70 | 2,370‡ | 2,400 | N/A |
| 2020 | 74 | 1,260 | 1,237 (98%) | N/A |
| 2020 | 74 | 1,569 | 1,523 (97%) | N/A |
| 2021 | 74 | 1,399 | 1,371 (98%) | N/A |
Notes.
* Percentage of those interviewed who responded to the diet question(s)
** N restricted to 5-day diet diaries only.
† In 1950, 2014-2015, and 2020-2021 no food diaries were collected.
‡ N from postal questionnaire.