Time trends in exposure of cattle to bovine spongiform encephalopathy and cohort effect in France and Italy: value of the classical Age-Period-Cohort approach

Table 2 Data available and data included in the analysis.

	Data available*		Data included		Data categorisation**			Reference groups***
	Number of tested animals	Number of BSE cases	Number of tested animals	Number of BSE cases	Age (year)	Birth cohort	Period (calculated)	Cohort	Age	Period
France	17,306,300	660	17,248,284⁽¹⁾	633⁽²⁾	2 to 33	1971 to 2005	1999 to 2007	1994/1995	6	2001
Italy	4,692,377	141	4,506,951⁽³⁾	131⁽⁴⁾	2 to 12	1988 to 2005	1999 to 2007	1996	5	2001

* data available from the implementation of complete active surveillance in the countries (January 2001 in Italy, July 2001 in France) to 31 December 2007.
** one-year intervals were used to define age groups and birth cohorts. The period was calculated using the relationship: period = age + cohort.
*** the reference groups chosen were the groups with the highest unadjusted prevalence. If necessary, a second model was fitted with the groups with the highest adjusted prevalence as a reference.
⁽¹⁾ 58,002 animals with unknown date of birth were removed.
⁽²⁾ 14 atypical cases, three imported cases, nine secondary cases and one case with unknown date of birth were removed.
⁽³⁾ 16,248 animals under two years old, and 19 animals with incorrect age and/or date of birth were removed. 169,156 animals over 12 years old were also removed, because only pooled data for these animals were available (class: "= 13 years").
⁽⁴⁾ three atypical cases, three classical cases over 12 years old and four imported cases were removed.

ISSN: 1746-6148