Potential effect modifiers for treatment with chiropractic manipulation versus sham manipulation for recurrent headaches in children aged 7–14 years: development of and results from a secondary analysis of a randomised clinical trial

Susanne Lynge; Werner Vach; Kristina Boe Dissing; Lise Hestbaek

doi:10.1186/s12998-023-00492-2

Table 1
Description of the 16 candidate variables
Candidate variable Formation from baseline questionnaire
Headache characteristics
Intensity of headache Numerical rating scale (NRS) from 0 to 10
Frequency of headache Number of days with headache per week. 1–2 days/3–5 day/nearly every day
Duration of headache 0.5–1 year/1–3 years/more than 3 years
Length of episodes < 2 h/half day/whole day/day and night
Absence from school 0/1–5/5–20/ > 20 days last year
Co-occurring symptoms Summary index based on four binary items: nausea, vomiting, light sensitivity, and sound sensitivity
Migraine-tension-type Continuous index based on severity and co-occurring symptoms (high values indicating migraine, low values tension type headache). Derived from previous analyses of the same cohort [17]
Variables identified from the literature Relationship with headache
Age Reported age in years Headache prevalence rises with age and there is a significant increase in headache prevalence after age 12 [18, 19]
Sport activity "0 times”,”1–3 times", or " > 3 times" Low physical activity is associated with recurrent headaches in adolescents [20–22]
Screen time “low”, “normal”, or “high” based on age-specific cut points for the self-reported screen time A forward head posture, as often assumed in front of computers, has been associated with neck and shoulder pain [5, 23]
Sleep duration “low”, “normal”, or “high” based on age-specific cut points for the self-reported sleep duration Poor quality of sleep is associated with headache in children [24–26] and this association is particularly evident in migraine [24]. Children with headache report more daytime symptoms of sleep disturbances, including fatigue, tiredness, and sleepiness [27]. Furthermore, excessive screen time may influence headache mediated by less sleep, and reduced sleep duration can be an indicator of an unhealthy lifestyle [28]
Trauma experience Summary index based on three items on lifetime trauma experience (no need for treatment, need for treatment, hospitalization) The cervical spine is the most commonly injured region of the spine in young children [29, 30] and thus cervicogenic headache might be a consequence of cervical dysfunction
History of concussion Binary item on lifetime experience of concussions In adults, headache associated with head injury is estimated to persist for 12 to 24 months after the injury in 20–30% [31]
History of neck pain Report of neck pain within the past year The cervical spine is the most commonly injured region of the spine in young children [29, 30] and thus cervicogenic headache might be a consequence of cervical dysfunction
Socioeconomic status Income is here considered as a proxy for socioeconomic status: self-reported annual income in 8 categories (labelled in 1000 €) Socioeconomically disadvantaged children are more prone to headache [32]
Headache in the family Presence of headache in the parents: “none”, “one parent “, or “both parents” A history of headache in a first-degree family member has been reported in up to 72% of children with headache with a predominance of maternal headache[19, 25, 33, 34]

Candidate variable	Formation from baseline questionnaire
Headache characteristics
Intensity of headache	Numerical rating scale (NRS) from 0 to 10
Frequency of headache	Number of days with headache per week. 1–2 days/3–5 day/nearly every day
Duration of headache	0.5–1 year/1–3 years/more than 3 years
Length of episodes	< 2 h/half day/whole day/day and night
Absence from school	0/1–5/5–20/ > 20 days last year
Co-occurring symptoms	Summary index based on four binary items: nausea, vomiting, light sensitivity, and sound sensitivity
Migraine-tension-type	Continuous index based on severity and co-occurring symptoms (high values indicating migraine, low values tension type headache). Derived from previous analyses of the same cohort [17]
Variables identified from the literature		Relationship with headache
Age	Reported age in years	Headache prevalence rises with age and there is a significant increase in headache prevalence after age 12 [18, 19]
Sport activity	"0 times”,”1–3 times", or " > 3 times"	Low physical activity is associated with recurrent headaches in adolescents [20–22]
Screen time	“low”, “normal”, or “high” based on age-specific cut points for the self-reported screen time	A forward head posture, as often assumed in front of computers, has been associated with neck and shoulder pain [5, 23]
Sleep duration	“low”, “normal”, or “high” based on age-specific cut points for the self-reported sleep duration	Poor quality of sleep is associated with headache in children [24–26] and this association is particularly evident in migraine [24]. Children with headache report more daytime symptoms of sleep disturbances, including fatigue, tiredness, and sleepiness [27]. Furthermore, excessive screen time may influence headache mediated by less sleep, and reduced sleep duration can be an indicator of an unhealthy lifestyle [28]
Trauma experience	Summary index based on three items on lifetime trauma experience (no need for treatment, need for treatment, hospitalization)	The cervical spine is the most commonly injured region of the spine in young children [29, 30] and thus cervicogenic headache might be a consequence of cervical dysfunction
History of concussion	Binary item on lifetime experience of concussions	In adults, headache associated with head injury is estimated to persist for 12 to 24 months after the injury in 20–30% [31]
History of neck pain	Report of neck pain within the past year	The cervical spine is the most commonly injured region of the spine in young children [29, 30] and thus cervicogenic headache might be a consequence of cervical dysfunction
Socioeconomic status	Income is here considered as a proxy for socioeconomic status: self-reported annual income in 8 categories (labelled in 1000 €)	Socioeconomically disadvantaged children are more prone to headache [32]
Headache in the family	Presence of headache in the parents: “none”, “one parent “, or “both parents”	A history of headache in a first-degree family member has been reported in up to 72% of children with headache with a predominance of maternal headache[19, 25, 33, 34]