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Biomedical subjects

P R Knudsen

Publications and source records attributed to P R Knudsen.

8 recordsLinked to original sources
PubMed1998

Iodine intake and the pattern of thyroid disorders: a comparative epidemiological study of thyroid abnormalities in the elderly in Iceland and in Jutland, Denmark.

Thyroid abnormalities are common in all populations, but it is difficult to compare results of epidemiological studies, because different methods have been used for evaluation. We studied the importance of the population iodine intake level for the prevalence rate of various thyroid abnormalities in elderly subjects. Random samples of elderly subjects (68 yr) were selected from the central person registers in Jutland, Denmark, with low (n = 423) and, in Iceland, with longstanding relatively high (n = 100) iodine intake. Females from Jutland had a high prevalence of goiter or previous goiter surgery (12.2%), compared with males from Jutland (3.2%) and females (1.9%) and males (2.2%) from Iceland. Abnormal thyroid function was very common in both areas, with serum TSH outside the reference range in 13.5% of subjects from Jutland and 19% of those from Iceland. In Jutland, it was mainly thyroid hyperfunction (9.7% had low, 3.8% had high serum TSH), whereas in Iceland, it was impaired thyroid function (1% had low, 18% had high serum TSH). All subjects with serum TSH more than 10 mU/L had autoantibodies in serum, but antibodies were, in general, more common in Jutland than in Iceland. Thus, thyroid abnormalities in populations with low iodine intake and those with high iodine intake develop in opposite directions: goiter and thyroid hyperfunction when iodine intake is relatively low, and impaired thyroid function when iodine intake is relatively high. Probably, mild iodine deficiency partly protects against autoimmune thyroid disease. Thyroid autoantibodies may be markers of an autoimmune process in the thyroid or secondary to the development of goiter.

Aged↗
PubMed1993

Amelioration of some pregnancy-associated variations in thyroid function by iodine supplementation.

Knowledge of the effect of differences in iodine intake levels on public health in areas with no endemic goiter is limited. Groups at risk when iodine intake is relatively low are pregnant and lactating women and their newborns. A prospective randomized study was performed to evaluate the effect of iodine supplementation in an area where the median daily iodine excretion in urine is around 50 micrograms. Fifty-four normal pregnant women were randomized to be controls or to receive 200 micrograms iodine/day from weeks 17-18 of pregnancy until 12 months after delivery. In the control group, serum TSH, serum thyroglobulin (Tg), and thyroid size showed significant increases during pregnancy. These variations were ameliorated by iodine supplementation. Iodine did not induce significant variations in serum T4, T3, or free T4. Cord blood Tg was much lower when the mother had received iodine, whereas TSH, T4, T3, and free T4 levels were unaltered. The results suggest that a relatively low iodine intake during pregnancy leads to thyroidal stress, with increases in Tg release and thyroid size. However, the thyroid gland is able to adapt and keep thyroid hormones in the mother and the child normal, at least under normal circumstances, as evaluated in the present study. It is not known whether this stress is sufficient to be of importance for late development of autonomous thyroid growth and function.

Adult↗
PubMed1991

[Periventricular cerebral hemorrhage in children with very low birth weights in the county of North Jutland. Retrospective study].

The object of this investigation was to determine the frequency of intracerebral periventricular haemorrhage in neonates with very low birthweights in an unselected material from the County of North Jutland. During the years 1988-1989 a total of 86 infants with low birthweights were born in the county. Intracerebral periventricular haemorrhage was diagnosed by means of ultrasonic scanning of the cerebrum and/or postmortem examination. Seven infants had to be excluded as neither of these examinations had been performed. The material thus consisted of 79 infants with a median weight of 1,196 gram (range 565-1,500 g) and a median gestational age of 30 weeks (range 25-37 weeks). Periventricular haemorrhage was found in a total of 13 infants, corresponding to 16% and the haemorrhages were found mainly in infants with gestational ages less than or equal to 29 weeks (32%). Haemorrhages with involvement of the parenchyma and/or dilation of the ventricular system comprised more than half of the cases of haemorrhage (8 out 13). The frequency of periventricular haemorrhage fell with gestational ages less than or equal to 30 weeks and the haemorrhages were less extensive. The respiratory distress syndrome and asphyxia were found to important risk factors for the development of periventricular haemorrhage.

Cerebral Hemorrhage↗
PubMed1988

Urinary iodine excretion is low and serum thyroglobulin high in pregnant women in parts of Denmark.

In the Randers area of Denmark urinary iodine excretion (which reflects iodine intake) was found to be much lower than recommended intake levels, both in women in late pregnancy [52(23-118) micrograms iodine/g creatinine, median, range, n = 20] and in non-pregnant controls [42(23-71), n = 20]. Serum thyroglobulin which is high in iodine deficiency was 32.5 micrograms/l (median) (range 10.5-78.0) in the control women and considerably higher in the pregnant women [67.0 micrograms/l (9.0-385)]. This increase was probably due to the extra iodine requirement of pregnancy which was not satisfied with an adequate increase in iodine intake. The results may suggest that pregnant women in this area should receive iodine supplementation and that a general program of iodine supplementation should be considered.

Adult↗