Table 3.

Unadjusted associations between fat mass of the F3 population according to whether their grandfathers or great-grandfathers had started smoking regularly before the onset of puberty (< 13).

Smoked pre-puberty	All F3’s			F3 males			F3 females
	na	MD [95% CI]	P	na	MD [95% CI]	P	na	MD [95% CI]	P
Fat mass at 17				Fat mass at 17			Fat mass at 17
MGF	67	0.48 [− 1.91, 2.87]	0.693	26	0.38 [− 3.25, 4.01	0.838	41	− 0.32 [− 3.10, 2.46]	0.821
PGF	31	3.58 [0.20, 6.96]	0.019	12	2.92 [− 1.87, 7.71]	0.231	19	3.54 [− 0.51, 7.59]	0.043
MGMF*	20	2.64 [− 1.74, 7.01]	0.237	9	6.24 [0.23, 1.22]	0.021	11	− 0.65 [− 5.97, 4.66]	0.809
MGFF*	15	2.99 [− 2.03, 8.01]	0.242	6	− 1.59 [− 8.37, 5.18]	0.642	9	5.35 [− 1.01, 11.7]	0.050
Fat mass at 24				Fat mass at 24			Fat mass at 24
MGF	50	0.48 [− 2.35, 3.30]	0.740	16	− 1.37 [− 5.95, 3.22]	0.559	34	0.84 [− 2.67, 4.34]	0.639
PGF*	25	3.10 [− 0.93, 7.14]	0.066	7	− 4.16 [− 10.9, 2.54]	0.222	18	5.49 [0.50, 10.5]	0.016
MGMF	12	2.64 [− 2.91, 8.20]	0.350	< 5	0.26 [− 8.35, 8.86]	0.953	8	3.31 [− 3.69, 10.3]	0.352
MGFF	16	4.17 [− 1.07, 9.41]	0.060	7	2.15 [− 4.65, 8.95]	0.532	9	6.10 [− 1.31, 13.5]	0.053

Comparisons are with all ancestors who had started smoking between ages 13 and 16. P values in bold are using 1-tailed tests since the hypothesis was that there would be excess fat mass for early smokers.

MD, mean difference; CI, confidence interval; MGF, maternal grandfather; PGF, paternal grandfather; MGMF, maternal grandmother’s father; MGFF, maternal grandfather’s father.

^aThe number of grandchildren and great-grandchildren whose ancestor started smoking regularly < 13 years.

*Statistically significant interaction between the sexes.