Iodine fortification may influence the age-related change in thyroid volume: a longitudinal population-based study (DanThyr)

TY - JOUR

T1 - Iodine fortification may influence the age-related change in thyroid volume

T2 - a longitudinal population-based study (DanThyr)

AU - Krejbjerg, Anne

AU - Bjergved, Lena

AU - Pedersen, Inge Bülow

AU - Carlé, Allan

AU - Jørgensen, Torben

AU - Perrild, Hans

AU - Ovesen, Lars

AU - Rasmussen, Lone Banke

AU - Knudsen, Nils

AU - Laurberg, Peter

PY - 2014/4

Y1 - 2014/4

N2 - Objective: To assess the individuals' thyroid volume changes after the mandatory nationwide iodine fortification (IF) program in two Danish areas with different iodine intake at baseline (Copenhagen, mild iodine deficiency (ID) and Aalborg, moderate ID). Design: A longitudinal population-based study (DanThyr). Methods: We examined 2465 adults before (1997) and after (2008) the Danish IF of salt (2000). Ultrasonography was carried out by the same sonographers using the same equipment, after controlling performances. Participants treated for thyroid disease were excluded from analyses. Results: Overall, median thyroid volume had increased in Copenhagen (11.8-12.2 ml, P=0.001) and decreased in Aalborg, although not significantly (13.3-13.1 ml, P=0.07) during the 11 years of follow-up. In both regions, there was an age-related trend in individual changes in thyroid volume from baseline to follow-up; thyroid volume increased in women <40 years of age and decreased in women >40 years of age. In a multivariate regression model, higher age at entry was a predictor (P<0.05) for thyroid volume decrease >20% during the follow-up period (women aged 40-45 years: odds ratio (OR) 4.3 (95% CI, 2.2-8.2); women aged 60-65 years: 5.8 (2.9-11.6)) and individuals of higher age were also less likely to have an increase in thyroid volume (women aged 40-45 years: OR 0.2 (0.1-0.3); women aged 60-65: OR 0.3 (0.2-0.4)). Conclusions: Age-dependent differences in thyroid volume and enlargement had leveled out after the Danish iodization program. Thus, the previously observed increase in thyroid volume with age may have been caused by ID.

AB - Objective: To assess the individuals' thyroid volume changes after the mandatory nationwide iodine fortification (IF) program in two Danish areas with different iodine intake at baseline (Copenhagen, mild iodine deficiency (ID) and Aalborg, moderate ID). Design: A longitudinal population-based study (DanThyr). Methods: We examined 2465 adults before (1997) and after (2008) the Danish IF of salt (2000). Ultrasonography was carried out by the same sonographers using the same equipment, after controlling performances. Participants treated for thyroid disease were excluded from analyses. Results: Overall, median thyroid volume had increased in Copenhagen (11.8-12.2 ml, P=0.001) and decreased in Aalborg, although not significantly (13.3-13.1 ml, P=0.07) during the 11 years of follow-up. In both regions, there was an age-related trend in individual changes in thyroid volume from baseline to follow-up; thyroid volume increased in women <40 years of age and decreased in women >40 years of age. In a multivariate regression model, higher age at entry was a predictor (P<0.05) for thyroid volume decrease >20% during the follow-up period (women aged 40-45 years: odds ratio (OR) 4.3 (95% CI, 2.2-8.2); women aged 60-65 years: 5.8 (2.9-11.6)) and individuals of higher age were also less likely to have an increase in thyroid volume (women aged 40-45 years: OR 0.2 (0.1-0.3); women aged 60-65: OR 0.3 (0.2-0.4)). Conclusions: Age-dependent differences in thyroid volume and enlargement had leveled out after the Danish iodization program. Thus, the previously observed increase in thyroid volume with age may have been caused by ID.

KW - Adolescent

KW - Adult

KW - Age Factors

KW - Aged

KW - Cross-Sectional Studies

KW - Denmark

KW - Female

KW - Food, Fortified

KW - Goiter

KW - Humans

KW - Iodine

KW - Longitudinal Studies

KW - Male

KW - Middle Aged

KW - Organ Size

KW - Sodium Chloride, Dietary

KW - Thyroid Gland

KW - Young Adult

U2 - 10.1530/EJE-13-0918

DO - 10.1530/EJE-13-0918

M3 - Journal article

C2 - 24399250

SN - 0804-4643

VL - 170

SP - 507

EP - 517

JO - European Journal of Endocrinology

JF - European Journal of Endocrinology

IS - 4

ER -