Table 1.

The number of observations of each variable and pairwise overlap between variables.

	Alcohol at T1	Alcohol at T2	Smoking at T1	Smoking at T2
Alcohol at T1	3394
Alcohol at T2	2074	3064
Smoking at T1	2582	1929	3181
Smoking at T2	2123	2464	2336	3203

Note. The study sample comprised 4895 individuals, of whom 3983 and 3803 individuals provided data at waves 1 and 2, respectively. The number of observations per variable are listed along the diagonal (highlighted). The off-diagonal values indicate the number of observations of pairwise overlap between variables.