few indicating that they had taken up smoking between surveys (Additional file 1: Table S1). Among current smokers at baseline who completed the 3-year resurvey, around one-third indicated that they were no longer smoking at resurvey, with those smoking fewer cigarettes per day being more likely to quit (Additional file 1: Table S1).Table 2 Smoking habits among current and former smokers, by sex Men Women Never-smoker 45,251 (50%)74,034 (65%) Current smoker 7,625 (8%)8,143 (7%)Smoking duration (years)Mean ± SD39.9 ± 9.837.1 ± 8.8<20124 (1.6%)205 (2.5%)20–342,143 (28%)3,085 (38%)35–493,869 (51%)3,814 (47%)≥501,063 (14%)541 (7%)Cigarettes/dayMean ± SD18.9 ± 10.416.6 ± 8.6≤142,308 (30%)3,016 (37%)15–242,931 (38%)3,324 (41%)≥252,222 (29%)1,632 (20%)Age at starting smoking (years)Mean ± SD17.6 ± 5.218.7 ± 6.1<13525 (7%)222 (3%)13–173,741 (49%)3,736 (46%)18–252,408 (32%)2,863 (35%)≥25526 (7%)824 (10%) Past smoker 37,335 (41%)32,565 (28%)Smoking duration (years)Mean ± SD22.6 ± 12.719.8 ± 12.2<2015,669 (42%)16,305 (50%)20–3412,707 (34%)10,126 (31%)35–495,767 (15%)3,796 (12%)≥50888 (2%)351 (1%)Cigarettes/dayMean ± SD20.1 ± 13.815.2 ± 10.4≤1412,083 (32%)16,121 (50%)15–2415,004 (40%)11,036 (34%)≥259,725 (26%)4,910 (15%)Age at starting smoking (years)Mean ± SD17.5 ± 3.818.5 ± 4.7<131,439 (4%)469 (1%)13–1718,316 (49%)13,624 (42%)18–2514,238 (38%)14,363 (44%)≥251,621 (4%)2,600 (8%)Age at ceasing smoking (years)Mean ± SD40.1 ± 12.638.4 ± 12.5<253,421 (9%)4,109 (13%)25–349,616 (26%)9,207 (28%)35–449,548 (26%)7,461 (23%)45–547,627 (20%)6,354 (20%)≥555,259 (14%)3,776 (12%)Numbers may not add up to total due to missing
