Table 1 Descriptive data of study participants

Age in years, median (IQR)

600

37 (31–41)

Female, n (%)

600

325 (54)

Neck pain intensity^a, median (IQR)

598

2 (0–5)

Moderate or severe neck pain^b, n (%)

598

183 (31)

Neck Disability Index (NDI)^c, median (IQR)

464

26 (14–37)

Moderate or severe neck disability^d, n (%)

464

274 (59)

NDI headache item

464

0: No headaches at all, n (%)

80 (17)

1: Mild headaches that come infrequently, n (%)

100 (22)

2: Moderate headaches that come infrequently, n (%)

91 (20)

3: Moderate headaches that come frequently, n (%)

141 (30)

4: Severe headaches that come frequently, n (%)

33 (7)

5: Headaches almost all the time, n (%)

19 (4)

Headache dichotomised^e, n (%)

464

193 (42)