北海道地方の海岸性甲状腺腫の研究 第一報

抄録

In 1889, Takenaka first described prevalence of goiter in Esashi, the seashore district of Hokkaido. Further studies on pathological and endemic views have been reported by Takeda, Miyamoto, Shimpo and Inoue. According to these data, the prevalence of goiter in the Hidaka District, Rishiri-Rebun Islands and Shakotan Insula was 8.9%, 36.3% and 10.9%, respectively. The goiterous patients in these areas take large amounts of Kombu, a sort of seaweed which is rich in iodine, as a sidedish or as seasoning for the usual diet.
Since 1960, systematic investigations of this peculiar goiter have been carried out. In this paper, prevalence and geographical distribution, the nutritional environment, intake and output of iodine, and therapy are reported as the first part of our study. 1. Prevalence and geographical distribution
Seven thousand nine hundred and seventy schoolchildren, 7 to 18 years of age, including 4,726 in the Hidaka District, 2,298 in Rishiri Isl. and 946 in Rebun Isl., were investigated. Size of goiter was classified according to Shichijo's criteria, Dieterle's modification.
The incidence of goiter was calculated 6.6%, 8.9% and 2.7% in Hidaka District, Rishiri Isl. and Rebun Isl., respectively. In each area, girls were predominant : the ratio of female to male was from 2 : 1 to 10 : 1. Control studies were performed on school children of Sapporo city, and the incidence of goiter was 1.3%.
The 2nd degree size of goiter was found in 75.2% among 539 goitrous patients, 3rd degree in 21.5% and over the 4th degree in 3.3%, but in the Hidaka District the enormous goiter, over the 4th degree, was found in 16 cases.
The incidence of the goitrous patients with family history of goiter was 4 to 5%.
The incidence of goiter reached the peak at 12 to 14 years of age in both sexes.
The thyroid gland was diffuse on palpation in 97.4% of 539 cases, and nodular in only 2.6%.
2. Clinical findings
All of the 539 patients revealed clinically euthyroid states : hyperthyroidism or hypothyroidism, hoarsness and dyspnea ; congenital deafness or mutism was not found.
3. Histological picture
Histological picture of the thyroid gland of 7 goitrous patients in Hidaka District was examined. The findings of Struma colloides macrofollicularis, that represent a enlargement of follicles and colloid storage without abnormal cell-infiltration, were seen in 6 cases, and Struma colloides microfollicularis or Struma foetalis in the other case.
4. Nutrition Survey
Intake of foodstuffs was investigated in 8 families whose occupation was fishing, chiefly seaweed “Kombu” collecting. Five families had a history of goiter and 3 had not. Daily intake of nutriments throughout the four seasons were calculated according to the method of National Nutrition Survey of Welfare Ministry. It was found that most nutritional materials such as protein, carbonhydrate and Vitamin-A, were sufficient. The seaweed, chiefly Kombu, of 16.1 gm. which amounts to three times the average of Hokkaido Nutritional Survey in 1961 was taken. Excessive intake of other foodstuffs containing a goitrogen were not recognized.
5. Urinary inorganic iodine excretion
Five cases of goitrous patients in Hidaka District were examined for urinary inorganic iodine excretion, that was measured by Gross's method, under the usual diet in this area. These patients excreted up to 23mg. of inorganic iodine per day, whearas control non-goitrous patients on a normal diet at Hokkaido University Hospital excreted 1.5mg. and those on a iodide-restricted diet excreted 150, μmg.
6. Response to treatment
Fifty cases of goitrous patients in the Hidaka District were administrated desiccated thyroid or L-Triiodothyronine. In 72.5%, a disapperance or decrease in size of goiter was obtained. A more effective response was noted in the 10-to 15-year old or those having a smaller size of goiter.