Table 2.

Present study compared with previous studies on population, demography and incidence rates

Study (year published)	Simonet et al. (1984)	Krøner et al. (1989)	Nordquist and Petersson (1995)	Owens et al. (2007)	Owens et al. (2009a, b)	Zacchilli and Owens (2010)	Present study (2010)
Population	USA, Olmsted	Denmark	Sweden	USA	USA	USA	Norway
	Minnesota	Aarhus	Malmø	Military	Military	Electronic	Oslo
	General	General	General	Selected	Selected	Database	General
	Rural/urban	Urban	Urban	Academy	National	National	Urban
Population at risk	880 000	1 268 765	230 056	4134	11 680 893	1.46 billion	575 475
Study period	10 years 1970–1979	5 years 1980–1984	1 year 1987	1 year 2004–2005	9 years 1998–2006	5 years 2002–2006	1 year 2009
Dislocations in total (n)						8940
	124	216	55	18	19 730	349 486 (model)	324
Dislocations primary (n, %)			55	12			151
			100%	66.7%	NR	NR	46.7%
Male proportion (%)	66.7%	53.3%	53%	NR	92.5%	71.8%	72.4%
Age(years)	Mean 36.4	Median 51	Mean 44 male 63 female	Mean 20	NR	Mean 35.4	Median 34
Incidence rate per 100 000 person-years
All dislocations both genders	11.2	17		435	169	23.9	56.3
Primary dislocations both genders	8.2 (*adjusted)	12.3	23.9	290	NR	NR	26.2
All dislocations men	11.2 (*adjusted)	9.1		NR	182	34.9	82.2
Primary dislocations men			27	NR		NR	34.8
All dislocations women	5.0 (*adjusted)	8.0		NR	90	13.3	30.9
Primary dislocations women			22	NR	NR	NR	17.9

^*Sex-and age-adjusted to the population structure of the United States in 1980.

NR, not rated.