Methods
We used two community based cohorts, the Swedish Mammography Cohort 25 26 and the Cohort of Swedish Men,27 to analyse the association of milk consumption and mortality and fracture rates.
Figure 1⇓ shows the study sample.
In 1987-90, all 90 303 women aged 39-74 years residing in two Swedish counties (Uppsala and Västmanland, both in central Sweden) received a postal invitation to a routine mammography screening.
Enclosed with this invitation was a questionnaire covering both diet (food frequency questionnaire) and lifestyle, which was completed by 74% of the women.
In 1997, a subsequent, expanded questionnaire wassent to those who were still living in the study area (response rate 70%).
In the present study 61 433 women in the Swedish Mammography Cohort with baseline data from 1987-90 and 38 984 with updated information from 1997 were available for analysis.
The Cohort of Swedish Men was created in the autumn of 1997.
All men, aged 45-79 years, residing in Örebro and Västmanland counties in central Sweden were invited to participate in the study (n=100 303).
Enclosed with this invitation was a questionnaire covering both diet (food frequency questionnaire) and lifestyle, which was completed by 48 850 men.
Despite the response rate of 49%, the Cohort of Swedish Men is considered representative of Swedish men in this age range in terms of age distribution, educational level, and prevalence of being overweight.
27 After exclusions, the final sample included 45 339 men (fig 1).