Iodine intake in Ireland--an update

Changes in Presentation of Celiac Disease in Ireland From the 1960s to 2015

BACKGROUND & AIMS

Celiac disease is an immune-mediated enteropathy characterized with high heterogeneity in presentation among genetically predisposed individuals. In recent years, a change in the phenotypic presentation of celiac disease has been reported. We studied clinical presentation, from 1960 through 2015, in Ireland, which has a high incidence of celiac disease.

METHODS

We performed a retrospective analysis of medical charts from patients diagnosed with celiac disease at 5 secondary referral centers in Ireland from 1960 through 2015 (n = 749; median age, 56 years; age range, 18-91 years). The cohort was divided into 5 groups based on year of diagnosis (≤1985, 1986-1995, 1996-2005, 2006-2010, or 2011 and later). We collected findings from clinical presentation at diagnosis; serology tests; small intestinal biopsy analyses; and patients' demographic, clinical, and family data. Presentations at diagnosis were classified according to the Oslo criteria as follows: classical (patients presenting with malabsorption), nonclassical (no signs or symptoms of malabsorption at presentation), or subclinical (below the threshold of clinical detection). The primary outcome was change in clinical presentation of celiac disease over time.

RESULTS

Of the 749 patients studied, 512 were female and 237 were male (ratio of 2.2:1). Female patients were diagnosed at younger ages than male patients (42 vs 47 years, respectively; P = .004), and had more immune-mediated conditions than male patients (35.7% for female patients vs 21.5% for male patients; P < .001). For patients diagnosed as adults (after the age of 18 years), the median age of diagnosis increased from 34.0 years during the period ≤1985 to median ages of 44-46 years after 1985 (P < .002). A smaller proportion of patients presented with classical features of celiac disease after 2010 (48.4%) than ≤1985 (85.2%); the proportion of patients with nonclassical or subclinical celiac disease increased from 14.8% ≤1985 to 51.6% after 2010 (P = .006 for each). Biopsies categorized as Marsh 3c decreased, from 52.2% in the period 1996-2005 to 22.5% in the period after 2010 (P = .003). The prevalence of associated thyroid disease has decreased during the study period, from 36.6% ≤1985 to 17.1% after 2010 (P = .039), whereas body mass index at diagnosis increased from 21.5 kg/m² ≤1985 to 24.8 kg/m² after 2010 (P < .001).

CONCLUSIONS

We found the clinical presentation of celiac disease changed significantly in Ireland from 1960 through 2015. The age of presentation in adulthood increased over this time period, as did the proportions of patients with nonclassical or subclinical disease.

Changing patterns of thyroid carcinoma

BACKGROUND

To assess changing trends in histological types of thyroid cancer in an Irish hospital over the past 30 years.

METHODS

Biographical data, tumour characteristics, treatment and outcome from 190 patients with thyroid carcinoma from 1970 to 2000 were reviewed retrospectively.

RESULTS

Detailed records of 190 patients with thyroid cancer were identified with a mean age at presentation of 50 years. From 1970 to 1979 the distribution of histological types was: papillary carcinoma; 9 patients (4.7%), follicular; 17 patients (8.9%), anaplastic; 9 patients (4.7%), medullary; 1 patient (0.5%) and lymphoma; 1 patient (0.5%). From 1980 to 1989 papillary carcinoma accounted for 32 patients (16.8%), follicular; 14 patients (7.3%), anaplastic; 13 patients (6.8%), medullary; 7 patients (3.7%) and lymphoma; 5 patients (2.6%). From 1990 to 1999 papillary cancer accounted for 48 patients (25.2%), follicular; 14 patients (7.3%), anaplastic; 8 patients (4.2%), medullary; 7 patients (3.7%) and lymphoma; 5 patients (2.6%). Survival rates were significantly better for those aged less than 45 years (P < 0.0001), female sex (P < 0.01) and those with papillary carcinoma (P < 0.01).

CONCLUSIONS

This study demonstrated a significant increase in the incidence of papillary carcinoma. This may be related to increasing dietary iodine intake and may be significant as papillary carcinoma is associated with a more favourable prognosis.

Iodine intake in pregnancy in Ireland — A cause for concern?

BACKGROUND

Adequate dietary iodine intake is necessary to maintain maternal thyroid function at a level permitting normal neuropsychological development of the foetus.

AIMS AND METHODS

To determine dietary iodine status by measuring urinary iodine excretion (UIE), proportional to dietary intake, in Irish mothers during the first trimester of pregnancy.

RESULTS

Median UIE showed seasonal variations, being lower in summer than in winter. The median values in pregnant women were, summer 45microg/l, winter 68microg/l. Equivalent values for controls were 43 and 91microg/l respectively. UIE required to achieve WHO recommended daily iodine intakes would be 120-180microg/l. In the Irish subjects UIE values suggestive of iodine deficiency (<50microg/l) were observed in 55% of pregnant women tested in summer and 23% in winter. Dairy milk iodine, a major dietary iodine source, showed similar variation.

CONCLUSIONS

While there is as yet no available evidence of widespread thyroid hypofunction in the Irish obstetric population, the findings are a cause of concern, which if confirmed by a more comprehensive investigation, may indicate the need for iodine prophylaxis.

Suppressive effect of iodine on DMBA-induced breast tumor growth in the rat

Concerning the suppressive effect of inorganic iodine on the growth of 7,12-dimethyl-benz(a)anthracene (DMBA)-induced breast tumor in female Sprague-Dawley (SD) rats, we previously reported that although iodine itself had a suppressive effect on the tumor growth, its effect was not as strong as that of MPA (medroxy-progesterone acetate). However, the combined medication of iodine at a low concentration + MPA showed a stronger effect than MPA alone. The purpose of the present study is to elucidate this mechanism of action by determining the uptake of the administered iodine into breast tumor tissue. Breast tumors were induced with DMBA in female SD rats, and these animals were treated with MPA + inorganic iodine at various concentrations for 4 weeks to determine tumor growth and tumor iodine content. In the comparison of tissue iodine content in growth-suppressive tumors with that in nonsuppressive tumors, the former showed a much higher iodine content. This suggests that direct uptake of inorganic iodine by breast tumors led to the suppression of tumor growth.

Thyroid disease and breast cancer

A review of the literature on the relationship between thyroid disorders and breast cancer does not provide conclusive evidence for the establishment of a causal relationship as breast cancer has been associated with hypothyroidism, hyperthyroidism and nontoxic goiter. Most reports on the association of thyroid enlargement and breast cancer have emanated from areas of endemic iodine deficiency and these reports have relied on neck palpation. The contribution of the present study is in the application of the highly sensitive technique of diagnostic ultrasound to the investigation of subtle changes in thyroid volume and anatomy in patients with breast cancer. The mean thyroid volume of 20.4 +/- 1.0 ml in 184 breast cancer patients was significantly greater than that of 12.9 +/- 1.2 ml in age-matched controls (p < 0.01). Also the number of individual patients with breast cancer having enlarged thyroid glands (73/184; 39.7%) was significantly greater than the corresponding number (13/150; 8.6%) in the control group (p < 0.001). There was a direct correlation between thyroid enlargement and breast tumour staging. Both mean thyroid volume and % of enlarged thyroids were identical in groups of patients scanned after (Retrospective Group) and before (Prospective Group) various therapies for breast cancer, thus excluding therapeutic intervention as a cause for thyroid enlargement. The results indicate a direct relationship between the two disorders perhaps involving a common growth stimulus and emphasise the importance of raising the consciousness of the coincidence of both disorders.

Management of patients with diffuse toxic goitre in Ireland, a country with low iodine intake

The present study was undertaken to examine the response rate of thyrotoxicosis in patients with diffuse toxic goitre to thiouracil drug treatment for 1 year in an Irish population, reported to have a low iodine intake. Evidence exists that a low iodine intake is associated with a high long-term remission rate for drug treatment of diffuse toxic goitre. Seventy-five patients participated with 45% of patients entering into long-term remission which has been maintained for a mean of 52.5 +/- 38.8 months. Fifty-five per cent of patients demonstrated relapse at a mean of 7.4 +/- 10.4 months following the withdrawal of thiouracil treatment. These findings were similar to those reported from countries with abundant iodine intake. The data in the present study confirms the usefulness of drug treatment for diffuse toxic goitre in an Irish population but the reported iodine deficiency does not appear to confer a particular advantage.