Management of overt and subclinical hypothyroidism. Factors influencing L-thyroxine dosage.

With the aim of establishing optimal dosage schedules, 171 women with either overt (OH, n = 80) or subclinical (SCH, n = 91) hypothyroidism were assessed before and 6 months after starting L-thyroxine (LT4) replacement therapy. Each group was further classified into four subgroups according to post-therapy serum TSH level, as follows: A) complete suppression; B) partial suppression; C) normal range and D) above normal range (insufficient response). In all subgroups, LT4 doses were higher for OH than for SCH, whether expressed as total daily dose (micrograms) or as a function of either actual or ideal body weight (micrograms/kg BW). In OH, LT4 dose was higher for subgroups A or B as compared with either C or D. In SCH, subgroup A received a larger dose than the other subgroups. Post-treatment serum thyroxine levels showed the same pattern for both OH and SCH. Mean LT4 dose was similar in patients with high and normal antithyroid antibodies and in patients with goiter and in those without it. In goitrous patients thyroid volume decreased in subgroup B, particularly in those patients that had elevated antithyroid antibodies, but not in subgroup C. In OH patients a significant negative correlation was found between daily LT4 dose per kg actual BW and actual BW, especially in subgroup C for patients with a body mass index > 27 kg/cm2 (r = -0.90, p < 0.001). In subgroup C of the SCH group, a negative correlation between LT4 dose and age was noticed. Both in OH and in SCH, LT4 dose per kg actual BW required to obtain a serum TSH within the normal range was lower in women with a body mass index (BMI) > 27 kg/m2 than in those with a BMI < or = 27 kg/m2. LT4 doses for subgroup C did not differ from those needed in hypothyroid patients with previous Graves' disease, in either OH or SCH patients.

Management of overt and subclinical hypothyroidism. Factors influencing L-thyroxine dosage.

With the aim of establishing optimal dosage schedules, 171 women with either overt (OH, n = 80) or subclinical (SCH, n = 91) hypothyroidism were assessed before and 6 months after starting L-thyroxine (LT4) replacement therapy. Each group was further classified into four subgroups according to post-therapy serum TSH level, as follows: A) complete suppression; B) partial suppression; C) normal range and D) above normal range (insufficient response). In all subgroups, LT4 doses were higher for OH than for SCH, whether expressed as total daily dose (micrograms) or as a function of either actual or ideal body weight (micrograms/kg BW). In OH, LT4 dose was higher for subgroups A or B as compared with either C or D. In SCH, subgroup A received a larger dose than the other subgroups. Post-treatment serum thyroxine levels showed the same pattern for both OH and SCH. Mean LT4 dose was similar in patients with high and normal antithyroid antibodies and in patients with goiter and in those without it. In goitrous patients thyroid volume decreased in subgroup B, particularly in those patients that had elevated antithyroid antibodies, but not in subgroup C. In OH patients a significant negative correlation was found between daily LT4 dose per kg actual BW and actual BW, especially in subgroup C for patients with a body mass index > 27 kg/cm2 (r = -0.90, p < 0.001). In subgroup C of the SCH group, a negative correlation between LT4 dose and age was noticed. Both in OH and in SCH, LT4 dose per kg actual BW required to obtain a serum TSH within the normal range was lower in women with a body mass index (BMI) > 27 kg/m2 than in those with a BMI < or = 27 kg/m2. LT4 doses for subgroup C did not differ from those needed in hypothyroid patients with previous Graves disease, in either OH or SCH patients.

[Iodine in school children. Relationship with incidence of goiter, socioeconomic group and salt intake]. / Ioduria en escolares. Relación con incidencia de bocio, nivel socioeconómico e ingesta de sal.

In order to evaluate iodine daily intake in 5-14 year-old school children urinary iodine excretion was measured in morning urinary samples of 134 school children. This value was corrected to microgram/ 24 h according to Jolin and Escobar del Rey's formula. Thyroid size was evaluated by two expert examiners following WHO criteria. Coincidence between both examiners was indispensable to establish goiter diagnosis. We evaluated urinary samples of 134 school children (117 normal and 17 goitrous). Urinary iodine excretion mean values were significantly different between Normal: 140.04 +/- 86.28 micrograms/24 h and Goitrous: 98.24 +/- 47.91 micrograms 24 h; p < 0.005). Goiter prevalence was found to diminish significantly when urinary iodine excretion was greater than 150 micrograms/24 h (p < 0.05). Similar mean urinary iodine excretion was observed in different socioeconomic groups. No significant differences were detected in the evaluation of two most common salt trademark consumer groups. In conclusion 1) iodoprophylaxis efficacy was assessed by urinary iodine excretion, a valid means to estimate iodine intake. Acceptable mean levels of iodine intake were found in the group under study, but the individual variability was important; 2) goitrous schoolchildren showed an iodine intake lower than normal and 3) the important variability observed in the evaluated data, the assessed relation between goiter and lower iodine intake, and the high frequency of insufficient iodine intake should justify a better control of iodoprophylaxis and a more widespread information dissemination among the population and perhaps iodine supplements in specific groups.