Cumulative AFB1 exposure-years were calculated by the following formula: exposure-years = (age - migration-years), where migration-years were defined as the years a person lived in non-exposure region of AFB1 (described in our previously published study [ 7]).
In-migration exceeded out-migration, adults younger than 30 years were the most migratory, and women migrate more than men.
Research has shown that the average wages earned by either male or female migrant workers during the first cycle of migration of two years is insufficient to cover pre-migration debts; hence the need for repeated migratory movements [ 45, 46].
Proximal migration at 2 years was the most frequently and most consistently reported migration value: 23 out of 26 RSA studies reported it.
However, the migration at 10 years was very similar between OA patients and RA patients (1.61 mm and 1.52 mm).
The mean migration at 10 years was 1.66 mm for HA, 2.25 mm for uncoated and 0.79 mm for the cemented group (p < 0.001).
The mean migration at 10 years was 1.61 mm for the osteoarthritis patients and 1.52 mm for the rheumatoid arthritis patients (p = 0.2, GLMM adjusted for fixation, age, sex, revision, and BMI).
For each city, the internal migration per year is described by two numbers: inflow and outflow.
The number of outliers varied between 2 and 4 depending on the RSA parameter and the time point. 1 patient who showed an abrupt 8.5 degrees of rotation of the stem by 3 months followed by minimal further migration up to 2 years was treated as an outlier and was excluded from the statistical analysis.
The magnitude of difference in migration from 1 to 10 years was less pronounced than the magnitude of difference in migration in the early postoperative period.
Gross migration rates (GMRs) and net migration rates (NMRs) by year were computed.
