High dietary caffeine consumption is associated with a modest increase in headache prevalence: results from the Head-HUNT Study

Table 1 Background data on participants according to use of caffeine

Variables	0–240 mg Caffeine	241–400 mg Caffeine	401–540 mg Caffeine	>540 mg Caffeine	Missing data
n	12,190	15,211	10,935	12,147	900
Gender, female (%)	59.6	55.8	53.8	45.5	59.0
Mean age (SD)	44.6 (19.3)	51.9 (16.7)	51.2 (15.5)	47.3 (13.7)	60.9 (18.1)
Years of education ≥13 (%)	27.2	21.4	18.2	14.4	5.6
Mean BMI (SD)	26.0 (4.2)	26.5 (4.0)	26.5 (4.0)	26.4 (4.0)	26.8 (4.5)
Current smoking (%)	13.9	19.8	29.6	49.1	29.0
High physical activity level^a (%)	10.8	7.4	7.6	9.0	3.6
Alcohol abstainers (%)	15.4	13.0	11.2	7.5	19.7
Previous myocardial infarction	2.9	3.6	3.3	2.6	5.7
Mean systolic blood pressure (SD)	135 (22)	140 (23)	139 (22)	136 (20)	146 (26)
Oral contraceptives (%)^b	22.3	9.6	6.5	5.7	11.0
Chronic musculoskeletal complaints^c	40.8	47.1	48.4	50.4	47.7

^aHigh physical activity level = ≥3 h/week with hard physical activity
^bUse of oral contraceptives among women <57 years
^cChronic musculoskeletal complaints = pain and/or stiffness in muscles and joints ≥3 months during the past year

ISSN: 1129-2377