Odds ratios (OR) and confidence intervals (95%) were converted into prevalence ratios (PR) as recommended by Schiaffino et al. [ 16].
We converted contraceptive prevalence rates provided in the surveys (with all married women as the denominator) to the percentage of use due to each contraceptive method, totaling 100% (with users of any contraceptive method as the denominator).
If needed for comparison to other studies, this can be converted into lifetime prevalence by collapsing the three last answer categories.
If a study only reported numbers, these numbers were converted to a prevalence proportion using the ratio of the number of individuals with the foot disease disorder or risk factor variable reported (numerator) and the number of the total sample size of the study (denominator).
To convert predicted age-specific prevalence values into numbers infected in each age group present at each school, the numbers of individuals of different age groups expected at each school was calculated.
In all the analyses that follow, these Mf loads are converted into population Mf prevalence levels using the expression P M,k) = 1−(1+M/k)−k, where P is the prevalence, M is the Mf density and k is the aggregation parameter of the negative binomial distribution given that Mf prevalence rather than intensity is the normal infection variable measured in the field.
Prevalence was converted into crude RRs, and ORs and RRs were treated as comparable measures of effect (RR).
As shown in Fig. 4, with increasing of risk alleles, the prevalence of subjects converting from IGT to NGT decreased significantly, and the prevalence of subjects remaining IGT or progressing to T2D increased significantly.
In the herds converting to organic farming the prevalence of SA infection at cow level was significantly higher before conversion (39%) compared to the conventional group (23%) (P = 0.03).
Estimated prevalence counts were converted to proportions of the population by using the mid-year ONS population estimates for 2007; these were the most recently available estimates and likely to be only slightly lower than the actual population at the end of 2008 (ONS, 2008a).
