Table 1.

Age distribution of the study population by the physical work demands group among men and women

Sex	Physical demands	N (%)	Mean age (STD)	Aged 30 years N (%)	Aged 40 years N (%)	Aged 50 years N (%)
Men	Low	305 527 (37.4)	45.1 (9.2)	11 969 (26.8)	52 079 (41.1)	52 022 (37.2)
	Mid	475 102 (58.2)	44.8 (9.4)	27 826 (62.2)	71 891 (56.4)	80 964 (57.9)
	High	35 920 (4.4)	42.3 (9.6)	4 935 (11.0)	3 193 (2.5)	6 933 (5.0)
	Total	816 549	44.8 (9.3)	44 730	127 506	139 919
Women	Low	310 301 (38.0)	44.3 (9.1)	18 150 (35.0)	52 079 (41.8)	54 167 (39.3)
	Mid	460 010 (57.8)	44.6 (9.3)	32 072 (61.8)	70 814 (56.9)	78 411 (56.8)
	High	25 842 (3.2)	45.1 (8.5)	1 637 (3.2)	1 640 (1.3)	5 422 (3.9)
	Total	796 153	44.3 (9.1)	51 859	124 533	138 000