i The father's occupation was coded on a six-point scale ranging between unskilled, semiskilled manual, skilled manual, skilled non-manual, managerial and professional.
The occupational social class of cohort members at 53 years was used as a marker of socioeconomic position, and was classified according to the Registrar General (1980) as either non-manual (managerial, professional, skilled professional ancillaries and service providers) or manual (skilled, non-skilled and agricultural workers).
In a smaller supplementary subset we repeated the analyses adjusting for current socioeconomic status of offspring, which had been assessed in a subset of the offspring born in 1950-55 according to the registrar general's classification of occupations with a six point scale ranging from unskilled, semiskilled manual, skilled manual, skilled non-manual, managerial to professional (fig 1).
This last involved a blurring of the distinction between conception and execution or between indirect and direct, nonmanual and manual, and managerial and nonmanagerial work; decentralization of decision making; flatter hierarchies; and broader and overlapping job descriptions and skill profiles.
In the analysis, NS-SEC categories were routine and manual, intermediate, managerial and professional, retired or home carer, sick or disabled and unable to work, long-term unemployed or never worked, in prison and other.
Each 1980 occupation code was then assigned to one of six social class codes based on occupation (V unskilled, IV partly skilled, IIIM-skilled non-manual, IIINM-skilled manual, II managerial and technical, I professional) from the 1980 OPCS Classification of Occupations.
There was also a relationship between SES and perception of risk (χ=46.11, df=4, P<0.001), with 32% of professional and intermediate (non-manual, non-managerial occupation) women reporting reduced risk compared to 10 15% of partly skilled and unskilled women.
The standard social classes have the summary terminology of: I Professional, II Managerial, III Skilled manual and non-manual workers, IV Partly skilled, V Unskilled.
Adult occupational social class was based on the longest-held occupation recorded at study entry (aged 40 59 years) using the Registrar General's occupational classification: I (professionals), II (managerial), III non-manual (semi-skilled non-manual), III manual (semi-skilled manual), IV (partly skilled) and V (unskilled).
Furthermore, if men were more likely to move from manual to professional or managerial work this may explain why knee ROA was still seen more commonly in men whose current or last job was in professional or managerial positions than in women.
7 Social class was determined according to the Registrar General's Social Class, and was classified into I/II (professional or managerial); III (skilled non-manual or skilled manual); IV (semi-skilled manual); V (unskilled manual); full time student or never worked.
