Relationship between chronic painful physical condition and insomnia.

BACKGROUND: A chronic painful physical condition (CPPC) can be a major cause of sleep disturbances. Few community-based surveys examined the specific relationship between these two conditions.

METHODS: Eighteen thousand, nine hundred and eighty participants aged 15 years or older from five European countries (the United Kingdom, Germany, Italy, Portugal and Spain) and representative of approximately 206 millions Europeans were interviewed by telephone. The interview included questions about sleeping habits, health, sleep and mental disorders. Painful physical conditions were ascertained through questions about medical treatment, consultations and/or hospitalizations for medical reasons and a list of 42 diseases. A painful physical condition was considered chronic when it lasted at least six months. Insomnia symptoms were defined as difficulty initiating or maintaining sleep or non-restorative sleep, present at least three nights per week, lasting at least one month, and accompanied by daytime consequences.

RESULTS: (1) The point prevalence of at least one CPPC was set at 17.1% (95% CI: 16.5-17.6%) in the sample. (2) Difficulty initiating sleep was found in 5.1% (95% CI: 4.8-5.4%) of the sample, disrupted sleep in 7.5% (95% CI: 7.2-7.9%); early morning awakenings in 4.8% (95% CI: 7.2-7.9%) and non-restorative sleep in 4.5% (95% CI: 4.2-4.8%). (3) More than 40% of individuals with insomnia symptoms reported at least one CPPC. (4) CPPC was associated with more frequent difficulty or inability to resume sleep once awake and a shorter sleep duration. (5) In middle-aged subjects (45-64 years of age), CPPC was associated with longer insomnia duration. At any age, insomnia with CPPC was associated with a greater number of daytime consequences (average of four consequences) than in insomnia without CPPC (average of 2.3 consequences). (6) In multivariate models, CPPC, especially backaches and joint/articular diseases, were at least as importantly associated with insomnia than were mood disorders with odds ratios ranging from 4.1 to 5.0 for backaches and from 3.0 to 4.8 for joint/articular diseases.

CONCLUSIONS: CPPC is associated with a worsening of insomnia on several aspects: a greater number of insomnia symptoms, more severe daytime consequences and more chronic insomnia situation. CPPC plays a major role on insomnia. Its place as major contributive factor for insomnia is as much important as mood disorders.