Randomisation is performed, stratified by centre, in blocks of variable length.
Randomization will be stratified by center using blocks of variable length from a reproducible SAS PROC PLAN code.
Randomisation will be by random permuted blocks of variable size from 6 to 10. Allocation will occur immediately following the assessment and advice session given by the treating physiotherapist.
The internet-based randomization will be conducted according to a central computerized randomization schedule, with a 1 1 treatment allocation ratio, stratified by centre, in blocks of variable size, to guarantee concealment.
Separate hierarchical regression models were fitted to explain the above two outcomes by entering blocks of variables sequentially: Step 1, demographics; Step 2, knowledge and information access; and Step 3, attitudinal variables.
The impact of potential confounders were evaluated by entering blocks of variables together with either CB-153 or p,p'-DDE as follows: in the first step, age and seafood intake were included in the model, and in the second step additionally smoking status, BMI, coffee intake and alcohol consumption were included in the model.
The randomization will be centralized and stratified by center and balanced in blocks of variable sizes.
The randomisation is in randomly permuted blocks of variable length, stratified by study centre, and by gestational age.
The randomisation schedule will be generated using permuted blocks of variable lengths by an independent statistician.
Randomisation will be performed externally by a statistical consultant using a computer-generated sequence allocation with permuted blocks of variable size, and stratified by gender.
