A physically active lifestyle is associated with lower long-term incidence of bipolar disorder in a population-based, large-scale study

International Journal of Bipolar Disorders

Table 1 Characteristics of the study population, presented for the whole cohort and by skiers and non-skiers separately

	All	Skiers	Non-skiers
	n = 395,369	n = 197,685	n = 197,684
Characteristics 1989–2010	Median (IQR) or n (%)	Median (IQR) or n (%)	Median (IQR) or n (%)
Age at baseline, y	36.0 (29.0–46.0)	36.0 (29.0–46.0)	36.0 (29.0–46.0)
Women	149,796 (38)	74,897 (38)	74,899 (38)
Education
Primary/elementary school (≤ 8 years)	49,344 (13)	14,538 (7.4)	34,806 (18)^a
Secondary school/high school (9–12 years)	176,571 (45)	76,635 (39)	99,936 (51)
Higher education/university (≥ 13 years)	166,133 (42)	106,147 (54)	59,986 (31)
Bipolar disorder at follow-up.	715	225	490^a

IQR interquartile range, y years, n numbers
^ap < 0·001. Group difference between skiers and non-skiers, estimated with Wilcoxon test (numeric variables) and Pearson’s χ² test (categorical variables). Only significant differences are noted in the table