However, large differences in prevalence between different studies were found, most likely arising from different use of diagnostic criteria and a difference in populations between primary and secondary care.
Within combined communities the overall prevalence of hypertension was 39.2% (95%CI: 35.9 42.5), half of whom (19.6% (16.9 22.3)) were newly detected, with no significant differences in prevalence between different ethnic groups.
There were no statistically significant differences in prevalence between the different years, although there was a slight declining trend in overweight and obesity over time (data not shown).
The aim of the present study was to elucidate whether Maa and Mah have a different potential to infect pigs that may explain the differences in prevalence between the two subspecies.
There were also no differences in prevalence between zygosity groups or between twins and their singleton siblings.
No differences in the one-year headache prevalence can be found for the groups with the lower income (p=0.96); in contrast the differences in prevalence between the two groups with the higher income and the groups with lower income were significant (P values between p=0.009 and p<0.001) (Table 3).
Fisher's exact test was used to test for differences in prevalence between the treatment groups.
Evidence for genetic risk includes familial aggregation [5], [7] and differences in prevalence between ethnic groups [8] [10] (caucasians of Northern European ancestries appear to be particularly susceptible).
The evidence of prevalence of this mutation is patchy with few studies looking at this locus and those that have show considerable differences in prevalence between countries.
We tested for significant differences in prevalence between island and mainland populations using Fisher's exact test, since all comparisons involved cells with low values.
*Chi-square test was used to compare differences in prevalence between males and females.
