Impact of maternal thyroid hormone in late pregnancy on adverse birth outcomes: A retrospective cohort study in China.

The purpose of this study was to explore the impact of maternal thyroid hormone dysfunction in late pregnancy on birth outcomes in a Chinese population. We retrospectively examined hospitalisation records and laboratory data between April 2016 and March 2017 and obtained results from 11,564 consecutive pregnant women with singleton births in which serum thyroid hormone had been examined together with birth outcomes. We assessed the association between maternal thyroid level and dysfunction with adverse birth outcomes based on regression analysis. Hyperthyroidism was associated with an increased risk of preterm birth (PTB, adjusted OR: 2.41, 95% CI: 1.83-3.17) and hypothyroidism was associated with an increased risk of small for gestational age (SGA, adjusted OR: 1.56, 95% CI: 1.10-2.22), while hyperthyroxinaemia was associated with a decreased risk of large for gestational age (LGA, adjusted OR: 0.64, 95% CI: 0.45-0.90). In addition, compared to women with normal FT3 and TSH (≥the 5th and ≤the 95th percentiles), women with high free triiodothyronine (FT3 >the 95th percentile) and low thyroid-stimulating hormone (TSH

Hyperthyroxinemia is positively associated with prevalent and incident type 2 diabetes mellitus in two population-based samples from Northeast Germany and Denmark.

BACKGROUND AND AIMS: A potential causal relationship between thyroid function and type 2 diabetes mellitus is currently under debate, but the current state of research is limited. Our aim was to investigate the association of thyroid hormone levels with prevalent and incident type 2 diabetes mellitus (T2DM) in two representative studies. METHODS AND RESULTS: Analyses are based on data from the Study of Health in Pomerania (SHIP), a German population based cohort with 4308 individuals at baseline and 3300 individuals at a five-year follow-up, and from INTER99, a Danish population-based randomized controlled trial with 6784 individuals at baseline and 4516 individuals at the five-year-follow-up. Serum thyroid-stimulating hormone (TSH) and free thyroxine (fT4) concentrations were measured in both studies, while free triiodothyronine was measured in SHIP only. T2DM was defined by self report or intake of anti-diabetic medication. Neither in SHIP nor in INTER99 we detected significant associations of serum TSH levels with prevalent or incident T2DM. Serum fT4 levels were significantly positively associated with prevalent T2DM in SHIP and INTER99. In longitudinal analyses baseline levels of fT4 were significantly positively associated with incident T2DM in SHIP (RR per pmol/L = 1.07; 95%-CI = 1.05-1.10), while this association barely missed statistical significance in INTER99 (RR per pmol/L = 1.03; 95%-CI = 0.99-1.06). In SHIP baseline fT3 levels were significantly associated with incident T2DM (RR per pmol/L = 1.21; 95%-CI = 1.16-1.27). CONCLUSION: We demonstrated positive associations of thyroid hormones with prevalent and incident type 2 diabetes mellitus suggesting that hyperthyroxinemia may contribute to the pathogenesis of this condition.

RISK FACTORS OF THYROID PATHOLOGY FORMATION IN OUTPATIENT PREGNANT POPULATION.

Several medical - biological and social - hygienic factors have been found to account for the definite increase in the incidence of thyroid gland disorders in reproductive age and pregnant women. Aim of our study was to identify the risk factors for development of thyroid gland pathology in outpatient pregnant women. Observational study - "case - control" study has been conducted at the base of David Gagua Hospital Ltd. Main (study) group involved 292 pregnant patients with established thyroid pathology. Control group included 58 conditionally healthy pregnant participants without any demonstrated thyroid pathology. Study of risk factors was performed by initial interviewing and specialized questionnaire recording process (so-called two-stage model of interviewing). Characteristics of diet, sleep, physical activity, including harmful habits, socio-economic and hereditary factors were studied; quantitative indices of risk for each component were calculated: odds ratio (OR) and attributable risk (AR), taking into account 95% confidence interval (CI). The Pearson's criterion χ2 with respective P value and the calculator developed by International Society of Evidence-based Medicine were used to obtain the final results. Statistically significant risk factors for development of thyroid pathology were identified, which included: Thyroid gland diseases and hereditary history of diabetes mellitus; low economic income, unfavorable living conditions, unhealthy dietary habits. Despite of the difficulty of assessment of causative relationship between above mentioned components, their strong correlation should be taken into account when defining the strategy of preventive measures, moreover the most part of identified risk factors are manageable.

Follow-up of newborns with elevated screening T4 concentrations.

OBJECTIVE: To determine the type and incidence of hyperthyroxinemic disorders detected by follow-up of infants with elevated screening total T4 (TT4) values. STUDY DESIGN: Infants born in Oregon with a screening TT4 measurement >3 SD above the mean were offered enrollment. Serum TT4, free T4, total T3, free T3, and thyroid-stimulating hormone concentrations were measured in study infants and their mothers. RESULTS: Over a 20-month period, 101 infants (51 boys) and their mothers enrolled in the study (of 241 eligible infants), from a total screening population of 80,884; 17 infants were identified with persistent hyperthyroxinemia (TT4 >16 microg/dL). Ten had thyroxine-binding globulin excess (1:8088), 5 had evidence for increased T4 binding but not thyroxine-binding globulin excess (1:16,177), and 2 had findings compatible with thyroid hormone resistance (1:40,442); the other 84 infants had transient hyperthyroxinemia. Sequence analysis revealed a point mutation in the thyroid hormone receptor-beta gene in one infant with thyroid hormone resistance; no mutation was identified in the other infant. CONCLUSIONS: Although neonatal Graves' disease occurs in approximately 1 in 25,000 newborn infants, we did not detect any case among 80,884 infants, most likely because their mothers were receiving antithyroid drugs. Although the other hyperthyroxinemic disorders in the aggregate occur frequently (1:4758) and may benefit from detection, in general they do not require treatment.

Prevalence of familial dysalbuminemic hyperthyroxinemia in serum samples received for thyroid testing.

The prevalence of familial dysalbuminemic hyperthyroxinemia (FDH), a condition sometimes mistaken for hyperthyroidism, has not been clearly established. I present a study of the prevalence of FDH in serum samples received for thyroid-function tests in a reference laboratory. A prospective study of 15,674 serum samples was carried out over 24 months, of which 13,232 cases were from women (84.42%) and 2442 were from men (15.58%). FDH was diagnosed in 26 cases, 22 in women and four in men. Therefore, the prevalence of FDH in the total number of samples from both sexes was 0.17%, 0.17% in women, and 0.16% in men, which is consistent with a dominant autosomal type of familial transmission. These findings demonstrate that cases of FDH occur frequently; therefore, every laboratory must be prepared to recognize them and thus avoid an incorrect diagnosis of the patient's thyroid function.