Nerve conduction in relation to vibration exposure - a non-positive cohort study

Table 1 Study population at baseline and follow ups, 1987-2008.

		1987	1987-1992^a	1997	2002	2008
Total		151	241	220	195	197
	Exposed^d	112(83)	181(108)	165(90)	141(57)	146(52)
	Unexposed	39	60	55	54	51
Returners from baseline (1987-1992)^c	Exposed^d				8(1)	26(13)
	Unexposed				3	2
Lost to Follow up	Exposed^e		9^b(7)	16(12)	32(22)	21(4)
	Unexposed		3^b	5	4	5

^a Baseline 1987-1992. Baseline consists of subjects entering the study in 1987 and 1992.
^b Lost to follow up between 1987 and 1992. The subjects are included in baseline (n = 241).
^c Subjects who were included at baseline, lost to follow up, but returned later to the study group in 2002 and/or 2008.
^d Subjects that currently are or previously have been exposed, the currently exposed in brackets.
^e Subjects that currently are or previously have been exposed, the currently exposed (based on the latest study) in brackets.

ISSN: 1745-6673