Clinically Diagnosed Insomnia and Risk of All-Cause and Diagnosis-Specific Disability Pension: A Nationwide Cohort Study

Table 1

Number of participants, person-years, all incident disability pensions (DPs), and incidence rates (IRs) by the adjusted factors.

	No. of exposed (%); (insomnia)^b	No. of participants (%)^a	Person-years	No. of incident DPs	IR^c
Age groups (year); Dec. 31, 2005
17–24	53 (>0)	846,146 (17)	4,133,741	15,026	3.64
25–34	97 (>0)	1,100,539 (22)	5,359,645	12,757	2.38
35–44	138 (>0)	1,182,671 (23)	5,760,797	26,222	4.55
45–54	196 (>0)	1,012,125 (20)	4,889,723	37,901	7.75
55–64	148 (>0)	887,441 (18)	3,601,907	50,286	13.96
Sex; Dec. 31, 2005
Male	321 (>0)	2,611,409 (52)	12,352,585	59,881	4.85
Female	311 (>0)	2,417,513 (48)	11,393,229	82,311	7.22
Education; Dec. 31, 2005^d
High educational level (more than 12 years)	226 (>0)	1,681,493 (33)	4,236,610	29,918	3.73
Medium educational level (10–12 years)	295 (>0)	2,379,667 (47)	11,313,525	68,007	6.01
Low educational level (0–9 years)	110 (>0)	919,722 (18)	8,010,680	39,464	9.32
Missing		48,040 (1)
Region of residence; Dec. 31, 2005^e
Larger cities	257 (>0)	1,896,500 (38)	8,968,370	44,142	4.92
Medium sized cities	215 (>0)	1,806,371 (36)	8,537,511	54,047	6.33
Smaller cities/rural areas	160 (>0)	1,326,051 (26)	6,239,934	44,003	7.05
Prior sickness absence; 2003–2005
No sickness benefits	319 (>0)	3,949,089 (79)	18,891,108	39,962	2.12
1–179 reimbursed sick-leave days	137 (>0)	833,572 (17)	3,943,005	27,193	6.90
180+ reimbursed sick-leave days	176 (>0)	246,261 (5)	911,700	75,037	82.30
Inpatient care; admission: 2000–2005
0 hospitalization days	239 (>0)	3,897,245 (78)	18,549,913	75,199	4.05
≤median summarized hospitalization days	160 (>0)	613,853 (12)	2,886,232	22,649	7.85
>median summarized hospitalization days	233 (>0)	517,824 (10)	2,309,668	44,344	19.20
Outpatient care; 2001–2005
0 specialist visits	15 (>0)	1,823,960 (36)	8,718,627	18,216	2.09
≤median summarized specialist visits	186 (>0)	1,836,577 (37)	8,759,807	37,182	4.24
>median summarized specialist visits	431 (>0)	1,368,385 (27)	6,267,380	86,794	13.86
Antipsychotics, anxiolytics, hypnotics, and sedatives combined^f; July–Dec. 2005
No prescribed medications	380 (>0)	4,801,705 (95)	22,792,763	107,788	4.73
At least one purchase of prescribed medications	252 (>0)	227,217 (5)	953,051	34,404	36.10
Total (missing excluded)	567	5,028,922 (4,980,882)

aObservations with missing data on any characteristic included in the study were excluded from the estimation of person-years, number of incident DPs and IRs.
bInsomnia in-/outpatient care (ICD-10: G47.0, main/secondary diagnosis).
cIRs per 100,000 person-years for all-cause DP; follow-up, 2006–2010.
dStatistics Sweden derives the attained “highest education” based on information regarding education according to the Swedish Standard Classification of Education. We classified SES based on education into three commonly used categories.
e“Region of residence” is based on “H-regions,” that is, homogenous regions regarding the population base, a categorization by Statistics Sweden based on municipalities according to the local and regional population bases following the scale urban-rural. We categorized these regions into three categories.
fThe Swedish Prescribed Drug Register contains data on drugs (ATC codes) but lacks information on indication of treatment, which prohibits identification of specific disease groups and it is not possible to link drugs bought over-the-counter to individual persons.