Dataset Information

Trend of lipid and thyroid function tests in adults without overt thyroid diseases: A cohort from Tehran thyroid study.

ABSTRACT:

Context

While the role of overt hypothyroidism in lipid disorders is clear, the association between dyslipidemia and subclinical thyroid diseases remains unclarified.

Objective

To examine lipid trends based on thyroid function over a 10-year period.

Design

This is a prospective population based cohort study.

Setting

General community.

Participants

2383 euthyroid participants, as well as those with subclinical thyroid diseases, in all residents of district 13 of Tehran were examined. Subjects who were on levothyroxine, anti-hyperthyroid drugs, and glucocorticoids, those with a history of thyroid surgery or RAI and pregnant women were excluded.

Main outcome measures

Lipid trends in Model 1 were adjusted for age and follow up duration, and in Model 2 gender-specific multivariate adjustments were performed for thyroid status, diabetes mellitus, smoking status, education, BMI, lipid lowering medications, age and follow up duration by using generalized estimating equations.

Results

In every four years of assessments, there were significant decreases in levels of all lipid parameters (all Ps <0.001) except for HDL-C, in which a decrescendo-crescendo trend was observed. The results did not change after adjusting for thyroid status, consumption of lipid lowering drugs during the follow-up period, or other variables. There were significant decreases in the prevalence of hypercholesterolemia and hypertriglyceridemia (all Ps <0.001) during the follow-up period.

Conclusion

During a 10 year follow-up, decrescendo trends were observed in levels of total cholesterol, triglycerides, which were not be accounted for by the consumption of lipid lowering drugs and thyroid status.

SUBMITTER: Ahi S

PROVIDER: S-EPMC6522003 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Trend of lipid and thyroid function tests in adults without overt thyroid diseases: A cohort from Tehran thyroid study.

Ahi Salma S Amouzegar Atieh A Gharibzadeh Safoora S Delshad Hossein H Tohidi Maryam M Azizi Fereidoun F Azizi Fereidoun F

PloS one 20190516 5

<h4>Context</h4>While the role of overt hypothyroidism in lipid disorders is clear, the association between dyslipidemia and subclinical thyroid diseases remains unclarified.<h4>Objective</h4>To examine lipid trends based on thyroid function over a 10-year period.<h4>Design</h4>This is a prospective population based cohort study.<h4>Setting</h4>General community.<h4>Participants</h4>2383 euthyroid participants, as well as those with subclinical thyroid diseases, in all residents of district 13 o ...[more]

PMID: 31095584

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Project description:Context:This review summarizes key findings of the Tehran thyroid study (TTS), a large scale community-based study with approximately a two decade follow-up, about the incidence, prevalence, and natural course of thyroid disorders as well as associations between thyroid diseases and metabolic syndrome (MetS), dysglycemia, and cardiovascular disease (CVD). Evidence Acquisition:PubMed, Scopus, and Web of Science databases, and the library of Research Institute for Endocrine Sciences were used to search for TTS articles. Articles were subdivided based on the fields of prevalence, incidence and natural course, and associations of thyroid function with the incident hypertension (HTN), MetS and CVDs. Results:The 2.5th and 97.5th percentiles of serum thyrotropin (TSH) were 0.32 and 5.06 mU/L, respectively. Estimated reference intervals (2.5th and 97.5th percentiles) for thyroid peroxidase antibody (TPOAb) levels were 1.5 - 32.8 and 2.1 - 35?IU/mL in men and women, respectively. Euthyroid persistency was 93.24% during 6 years. There was a negative association between free thyroxine (FT4) levels and insulin resistance. Decreasing FT4 values over time would predict MetS in euthyroid and subclinical hypothyroid subjects (TSH < 10 mU/L). The incidence of thyroid disorders in patients with diabetes, pre-diabetes and healthy controls was 14, 18, and 21 per 1000 person-years, respectively, indicating significantly lower incidence in individuals with diabetes compared to healthy controls. Serum FT4 within the reference range was positively associated with all blood pressure (BP) measures in the total population and in men; however, serum TSH was positively associated with only systolic BP (SBP), diastolic BP (DBP) and mean arterial pressure of men. No associations were found between various states of thyroid function and prevalence and incidence of CVD. Conclusions:A well designed cohort study aimed to investigate the gap in knowledge regarding thyroid disorders can generate many hypotheses to be examined in randomized controlled trials.

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Project description:BackgroundThe aim of the current study is to assess the prevalence of different categories of thyroid dysfunction and their associated risk factors among the modern urban population of Tehran, the capital of Iran.MethodsThe present investigation is a sub-study of the HAMRAH study, a population-based prospective study designed to assess the prevalence of traditional cardiovascular risk factors and their changes through a 10-year follow-up. 2228 (61% female) adults aged between 30 and 75 years old and with no overt cardiovascular diseases were selected through a multistage cluster randomized sampling. Blood levels of thyroid-stimulating hormone (TSH), thyroxin (T4), and triiodothyronine (T3) were measured with the aim of assessing the prevalence of abnormal thyroid function status among the modern urban Iranian population, and in order to report the total prevalence of participants with clinical hypo- or hyperthyroidism, the number of individuals taking thyroid-related drugs were added to the ones with overt thyroid dysfunction. A subgroup analysis was also performed to determine the associated risk factors of thyroid dysfunction.ResultsThe prevalence of thyroid dysfunction among the total population was 7% (95%CI: 5.9 - 8%) and 0.4% (95% CI: 0.1 - 0.6%) for subclinical and overt hypothyroidism, and 1.6% (95% CI: 1 - 2%) and 0.2% (95% CI: 0 - 0.3%) for subclinical and overt hyperthyroidism, respectively. Clinical thyroid dysfunction was detected in 10.3% of the study population (9.4% had clinical hypo- and 0.9% had clinical hyperthyroidism). In the subgroup analysis, thyroid dysfunction was significantly more prevalent among the female participants (P-value = 0.029).ConclusionsIn the current study, the prevalence of different categories of abnormal thyroid status, and also the rate of clinical hypo- and hyperthyroidism was assessed using the data collected from the first phase of the HAMRAH Study. In this study, we detected a higher prevalence of clinical and subclinical hypothyroidism among the Iranian population compared to the previous studies.

Project description:BackgroundNon-participation in cohort studies, if associated with both the exposure and occurrence of the event, can introduce bias in the estimates of interest. This study aims to identify factors associated with follow-up participation in Tehran Lipid and Glucose Study, a large-scale community-based prospective study in West Asia.MethodsA sample of 10,368 adults from TLGS was included in the analysis. All analyses were split according to sex and age groups (20-39, 40-59, and 60 years). The associations between socio-demographic, health, and lifestyle factors with response rate were identified using the Generalized Estimating Equations model.ResultsOver the median of 15.7 years of follow up the response rate was 64.5%. The highest response rate was observed in those aged 40-59 years for both sexes. Current smokers had lower odds of response in both sexes for all age groups, ranging from 0.51 to 0.74, p < 0.01. In young adults, being single (OR = 0.79, OR = 0.57, p ≤ 0.01, respectively for men and women) and unemployed (OR = 0.73, OR = 0.76, p ≤ 0.01, respectively for men and women) in both sexes, high physical activity in men (OR = 0.77, p < 0.01), high education (OR = 0.75, p = 0.02) and obesity (OR = 0.85, p = 0.05) in women were associated with lower response rate. For the middle-aged group, diabetes in men (OR = 0.77, p = 0.05) and hypertension (OR = 0.84, p = 0.05), and having a history of cancer (OR = 0.43, p = 0.03) in women were factors associated with lower response rates. Finally, interventions for both sexes (OR = 0.75, OR = 0.77, p ≤ 0.05, respectively for men and women) and being divorced/widow in women (OR = 0.77, p = 0.05) were the factors associated with the lower response rate in the elderly.ConclusionsLong-term participation was influenced by socio-demographic, health, and lifestyle factors in different sex- and age-specific patterns in TLGS. Recruitment strategies targeting these factors may improve participant follow-up in longitudinal studies.

Dataset Information

Trend of lipid and thyroid function tests in adults without overt thyroid diseases: A cohort from Tehran thyroid study.

Context

Objective

Design

Setting

Participants

Main outcome measures

Results

Conclusion

Publications

Trend of lipid and thyroid function tests in adults without overt thyroid diseases: A cohort from Tehran thyroid study.

Similar Datasets

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