TABLE 1.
Baseline characteristics of the study participants
| All participants | Intervention | Control | |
|---|---|---|---|
| Subjects n | 90 | 46 | 44 |
| Age years | 51.8±12.4 | 52.2±11.9 | 51.4±12.9 |
| Female | 67 | 72 | 61 |
| Race/ethnicity | |||
| Non-Hispanic White | 43 | 46 | 41 |
| Non-Hispanic Black | 11 | 13 | 9 |
| Asian/Pacific Islander | 31 | 28 | 34 |
| Hispanic/Latino | 14 | 13 | 16 |
| Education | |||
| High school graduate or less | 9 | 2 | 16 |
| Some college | 38 | 44 | 32 |
| College graduate or above | 53 | 54 | 52 |
| Employment status | |||
| Full-time | 59 | 67 | 50 |
| Part-time | 10 | 9 | 11 |
| Unemployed/retired/disabled | 31 | 24 | 39 |
| Family annual income US$ n=87# | |||
| <35000 | 15 | 13 | 17 |
| 35000–<55000 | 15 | 18 | 12 |
| 55000–<75000 | 18 | 11 | 26 |
| 75000–<100000 | 18 | 27 | 10 |
| 100000–<125000 | 13 | 16 | 10 |
| 125000–<150000 | 6 | 4 | 7 |
| ⩾150000 | 15 | 11 | 19 |
| DASH¶ score | 2.3±1.3 | 2.4±1.4 | 2.2±1.2 |
| Smoking status | |||
| Never-smoker | 74 | 81 | 68 |
| Current smoker | 6 | 4 | 7 |
| Ex-smoker | 20 | 15 | 25 |
| Pack-years of current or ex-smokers n=23# | 10.3±12.5 | 9.4±10.3 | 10.9±14.0 |
| Asthma onset age before 12 years by self-report | 29 | 26 | 32 |
| Atopy n=77#,+ | 74 | 72 | 76 |
| ACT | 14.9±3.7 | 15.2±3.8 | 14.6±3.6 |
| ACQ | 1.3±0.8 | 1.2±0.7 | 1.4±0.8 |
| FEV1 L n=88# | 2.6±0.8 | 2.5±0.9 | 2.7±0.7 |
| FVC L n=88# | 3.8±1.0 | 3.6±1.0 | 3.9±1.0 |
| FEV1/FVC n=88# | 68.5±11.3 | 67.8±11.1 | 69.3±11.5 |
Data are presented as mean±SD or %, unless otherwise stated. DASH: Dietary Approaches to Stop Hypertension (range 0–9 with higher scores indicating better DASH concordance); ACT: Asthma Control Test (range 5–25 with higher scores indicating better asthma control); ACQ: Asthma Control Questionnaire (range 0–6 with higher scores indicating worse asthma control); FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity.
denominator was <90 randomised participants because of missing data.
DASH scores were calculated based on combining nine nutrient targets (i.e. total fat, saturated fat, protein, cholesterol, fibre, magnesium, calcium, sodium and potassium). The intermediate target of each nutrient was half-way between the DASH target and population mean (based on the National Health and Nutrition Examination Surveys 2007–2008, latest data available at the inception of this study). For a nutrient, participants reaching the DASH target were assigned one point, those reaching the intermediate target were assigned a half-point, and those not meeting the intermediate target were given 0 points. The DASH score was the sum of points for all nine nutrients [12].
atopy was defined as any tested aeroallergen having a value ⩾0.35 based on ImmunoCAP Specific IgE testing. The types of allergies for which specific IgE tests were performed included dust mite (Dermatophagoides pteronyssinus), two types of animal dander (cat and dog), two grasses (ragweed and timothy grass) and tree (juniper cedar).