an increasing trendp = 0.075
a decreasing trendp = 0.492
However, an increasing trend in the incidence of mild CH ( p = 0.075) and a decreasing trend in severe CH ( p = 0.492) was detected when the severity of the disease was defined by fT4 concentration in the confirmatory test (mild = fT4 ≥ 5 pmol/l, severe <5 pmol/l) (Fig. 2 ).