The influence of parity on multinodular goiter prevalence in areas with moderate iodine deficiency

Abstract

Despite the observation that parity may increase the risk of thyroid carcinoma, very few studies have investigated the possible repercussion of parity on thyroid benign pathology. Recently, parity has been identified as one of the factors contributing to a larger thyroid size in healthy females. The aim of this work was to investigate a possible role for parity on the prevalence of multinodular goiter in iodine deficient areas. For this purpose, the reproductive histories of 2 cohorts of women, normal (Group I, 235 cases) and non-toxic multinodular goiter (NTMNG) affected (Group II, 274 cases) were compared. All subjects were euthyroid and had no previous history of thyroid function abnormalities. The number of full-term previous pregnancies (2.55+/-0.11 vs 1.77+/-0.10) and age (47.7+/-0.76 vs 42.3+/-0.83 yr) were found significantly higher (p<0.001) in multinodular goiter (MNG) patients than controls. Parity and age were found to be directly correlated (p<0.001), nevertheless the partial correlation coefficients demonstrated an independent and statistically significant difference for both variables between normal and NTMNG. Therefore, the independent effects of parity and age were further investigated. The effect of age on NTMNG prevalence seems to be weaker, in fact significant differences (p<0.001) for age between patients and controls were detected only when the effect of parity was absent (nulliparous), while with increasing gestations the effect of age disappeared. Our results indicate that age plays a minor role compared to parity which can therefore be considered as a stronger risk factor. In conclusion, the present study shows that, at least in iodine deficient regions, non-toxic multinodular goiter women show a statistically significant higher parity rate than healthy controls. Age may play a certain role but only when additional stronger risk factors are absent.

Iodine Status of Pregnant Women and Their Progeny in the Minho Region of Portugal

“…This observation provides additional evidence for ID. Unlike other studies, we did not find any relation between thyroid volume and age, previous pregnancies, socioeconomic status, urinary or breast milk iodine, or the progeny's thyroid volume (21)(22)(23)(24)(25)(26), but only with the fishconsumption rate (25).…”

“…In our study almost 14% of all pregnant women had gestational goiter, and heterogeneous echotexture patterns after pregnancy were often observed. This is in agreement with reports from other iodine-insufficient populations (23)(24)(25). In addition, the thyroid volume during pregnancy correlated with that observed after pregnancy, indicating that thyroid enlargement only partially reverted after delivery.…”

“…While urinary iodine excretion is the most appropriate indicator for assessing recent iodine intake in epidemiological studies, other indices such as goiter are clinical hallmarks of ID (1)(2)(3)(20)(21)(22)(23)(24)(25)(26). In our study almost 14% of all pregnant women had gestational goiter, and heterogeneous echotexture patterns after pregnancy were often observed.…”

Thyroid Function/Antibodies in Sudanese Patients with Preeclampsia

“…Incongruent with previous reports, the present results fail to demonstrate influences of parity and gestational age on maternal thyroid function/antibodies (28, 33–35). A cross-sectional study conducted in 50 non-pregnant women as a control group, 50 primiparae and 50 multiparae women showed increased serum levels of T4 and T3 in both groups, while serum level of TSH decreased significantly in the two groups (35).…”

“…A cross-sectional study conducted in 50 non-pregnant women as a control group, 50 primiparae and 50 multiparae women showed increased serum levels of T4 and T3 in both groups, while serum level of TSH decreased significantly in the two groups (35). Higher levels of thyroid hormones in multiparae women in iodine deficient regions may explain their higher risk to develop multinodular goiter (35).…”