|Ahead of print publication
Prevalence of hypothyroidism in Kannur; a coastal district in Kerala
TV Devaraj1, S Salina2
1 Department of General, Laparoscopic and Thoracoscopic Surgery, Aster MIMS Hospital, Kannur, Kerala, India
2 Department of Community Health Nursing, College of Nursing, Kannur, Kerala, India
|Date of Submission||14-Jan-2022|
|Date of Acceptance||17-Mar-2022|
|Date of Web Publication||13-May-2022|
Department of Community Health Nursing, College of Nursing, Thalassery, Kannur, Kerala
Source of Support: None, Conflict of Interest: None
Background: Hypothyroidism is an emerging health issue in India and worldwide. However, detail data related to the magnitude of the problem is lacking currently.
Materials and Methods: A cross-sectional, multicentric study was conducted at four villages in Kannur district of Kerala, to study the prevalence of hypothyroidism among the adult population. Thyroid abnormalities were diagnosed based on laboratory results (free thyroxin [FT4] and thyroid-stimulating hormone [TSH]). Participants with history of hypothyroidism and receiving levothyroxine therapy or those with serum FT4 ≤ 0.78 ng/dL and/or TSH ≥ 4.68 μIU/mL were categorized as hypothyroid. The prevalence of self-reported and undetected hypothyroidism was assessed.
Results: A total of 1084 adult male or nonpregnant female participants ≥ 18 years of age were enrolled, of which 508 were evaluated. The overall prevalence of hypothyroidism was 9.6%. 2.1% were already on levothyroxine therapy and is self-reported, whereas 7.48% were previously undetected. Higher proportion of female versus male (8.07 vs. 7.87) was diagnosed with hypothyroidism.
Conclusion: The prevalence of hypothyroidism was high, affecting approximately 9.6% of adult in the study population. Female gender (odds ratio = 1.791) were found to have significant association with hypothyroidism.
Keywords: A coastal district in Kerala, free T4, hypothyroidism, prevalence, prevalence of hypothyroidism in Kannur; thyroid-stimulating hormone
| Background|| |
Hypothyroidism is a common clinical disorder encountered by the health-care professionals. Untreated hypothyroidism can contribute to hypertension, dyslipidemia, infertility, cognitive impairment, and neuromuscular dysfunction. Hypothyroidism occurs as a result of failure of thyroid gland or insufficient or inadequate thyroid gland stimulation by the hypothalamus or pituitary gland. Thyroid gland failure results from autoimmune destruction (Hashimoto's disease), congenital abnormalities, infiltrative diseases, and iodine deficiency. Autoimmune thyroid disease is the most common etiology of hypothyroidism. The major causes of hypothyroidism typically present with other manifestations of hypothalamic or pituitary dysfunction.
The prevalence of hypothyroidism is increasing worldwide. Hypothyroidism is the most common thyroid disorders in India, affecting one in ten adults. The prevalence is 11%, compared to 2% in the United Kingdom and 4.6% in the USA. Iodized salt is highly recommended in India since 1983. Hypothyroidism is easy to detect and treatment is inexpensive too. Even then, patients with hypothyroidism are undetected and it affects their quality of life, work performance, and economic productivity. In the past, iodine deficiency was responsible for the thyroid problems. However, even after 30 years of implementation of the universal iodization program, hypothyroidism is still prevalent in the country.
Earlier, there was so-called iodine belt in North-Eastern part of India. Due to large contribution to national disease burden, lifestyle diseases and communicable diseases have been the priority health concerns in India. Since the implementation of the universal salt iodization (USI) program, India was supposed to undergo a transition from iodine deficiency to sufficient state. As per review studies conducted in the postiodization phase, there is a change in the thyroid status of the Indian population.
The prevalence of hypothyroidism varies considerably across the general population. The number of factors can influence the prevalence of this condition such as, the differences in the iodine status between populations, with higher prevalence in high iodine intake and in severely iodine-deficient populations.
Iodine deficiency could be a major public health concern throughout the globe. The most issue chargeable for iodine deficiency could be a low dietary offer of iodine. Once iodine necessities do not seem to be met, the resultant iodine deficiency causes adenosis and a series of useful and organic process abnormalities that are classified beneath the term iodine deficiency disorders. The United Nations agency recommends adding 20/40 mg of iodine per weight unit of salt to fulfill iodine necessities forward that the typical consumption of salt per capita is 10 g/day.
A retrospective analysis was performed at a tertiary cancer care hospital for 6 years. Of the 16,993 patients, 128 patients suffered from thyroid disorders (0.8%). The prevalence of thyroid disorders was considerably higher in females than males, 33.6% versus 66.4%.
A study was done to grasp the prevalence of hypothyroidism and its association with anti-thyroid peroxidase (TPO) protein among the adult ocean food intense population in Kerala. It had been a hospital-based cross-sectional study involving 300 patients. 30.4% of participants had thyroid pathology, the prevalence of hypothyroidism and subclinical hypothyroidism was 11.7. Anti-TPO protein was positive in 71.4%. There was a positive relation between hypothyroidism and anti-TPO protein suggesting thyroid pathology as a risk issue for hypothyroidism.
“Across the globe, with the arrival of iodization, reaction thyroid illness has become the foremost common reason behind gland disease.” Environmental factors aside from iodine deficiency may play a neighborhood in gland disease in Asian nation. “Goitrogens associate in cyanogenic exposure to toxic compounds have an adverse impact on iodine metabolism,” says Mithal. “The unregulated use of pesticides and exposure to endocrine disruptors may be a reason,” he suggests, adding that “Unclean water and exposure to industrial pollutants such as phenol and acid have conjointly been advised as causes.”
There have been few nation-wide studies conducted to identify the prevalence of hypothyroidism in India. In a coastal state like Kerala, only few studies were conducted to understand the hypothyroidism. The aim of the present study was to identify the prevalence of hypothyroidism among adults in Kannur district, a coastal region situated at the northern part of Kerala.
| Materials and Methods|| |
Study design and enrollment criteria
The ethical clearance for the study was obtained from the institutional ethical committee of the institution, where the one of the investigators is working. This was a cross-sectional multicentric study conducted at 4 villages from 4 Taluks in Kannur District, namely Muzhappilangad, Pattiam, Pattuvam, and keezhur from Kannur, Thalassery, Taliparamba, and Iritty taluks, respectively. These villages were selected randomly to ensure the representation of people from the whole district. The objective of the study was to identify the prevalence of hypothyroidism based on the assessment of thyroid hormone. All adults aged ≥18 years of age were invited to participate in medical camps organized by the investigators. All adults who attended the camp were screened using Zulewski's clinical score for hypothyroidism [Table 1]. A score of 0–2 points defined euthyroid. All adults with a score of >2 were given informed consent for the willingness to provide blood samples for laboratory investigation. Pregnant mothers and those who were on regular treatment such as lithium were excluded from this study.
Planning for the camps
The campaigning for the camp was done using different strategies. All the camps were conducted in schools. The information regarding the camp was disseminated through leaflets which were distributed through students, parents, and teachers in the concerned schools. The other strategies used were through the distribution of leaflet through the self-help group called “kudumbashree” and gram sabhas. The help was taken from volunteers, political parties, and natives of the villages. Banners were exhibited in areas covering 2 km around the camp venue. The medical camp was led by the team from multispecialty hospital nearby. The team includes a surgeon, laboratory technician, registered nurses, supporting staff, and a public relation officer. Enrollment of 1000 participants was planned to form a target population. Multistage cluster sampling technique was used [Figure 1] to select the target village.
|Figure 1: Multistage cluster sampling process for the selection of villages|
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All participants underwent a preliminary health assessment such as, anthropometry, blood pressure check, and temperature measurement and then were screened using Zulewski's clinical score for hypothyroidism. The participants with Zulewski's clinical score more than 2 were sent to the doctor and were further advised for the laboratory investigation. Informed consent was obtained before sample collection. A certified laboratory performed the hematological investigation. Assays for thyroid hormones (Free T4 and thyroid-stimulating hormone [TSH]) were performed by electrochemiluminescence immunoassay analyzer. Based on the thyroid function tests, the participants were classified as hypothyroidism, when free thyroxin (FT4) <0.78 ng/dL and/or TSH >4.68 μIU/mL. The participants are categorized into hyperthyroid when FT4 >2.19 ng/dL and/or TSH <0.465 μIU/mL.
Statistical analysis was performed using SPSS (version 25, IBM® SPSS® Statistics). The prevalence of hypothyroidism and hyperthyroidism was summarized as frequency and percentage. The odds ratio was calculated to identify the association between gender and hypothyroidism.
| Results|| |
The total number of participants enrolled for the 4 camps were 1084. The data collection period was from November 2019 to February 2020. Of the 1084 participants, the blood sample was collected from 508 participants after assessing Zulewski's clinical score. Of 508 participants, 388 were females and 120 were males. The mean age of study participants was 45.85 (range 18–89 years). The participants who have been under current or previous medication for hypothyroidism were 3.74%. A majority (87%) of the participants were using iodized salt [Table 2].
The prevalence of hypothyroidism in the study population was 9.6% (n = 508, confidence interval [CI] - 95%). The mean TSH and FT4 value among all individuals whose blood sample was sent for investigation were 2.06 μIU/mL and 3.09 ng/dL (n = 508, CI 95%). The odds ratio was calculated between gender and prevalence of hypothyroidism and was found to be 1.791. Higher proportion of female versus male (8.07% vs. 7.87%) was diagnosed with hypothyroidism [Table 3].
A total of 26 (5.11%) participants were having laboratory values suggestive of hyperthyroidism.
| Discussion|| |
The thyroid gland produces hormones that influence every cell, tissue, and organ in the body. Thyroid hormones regulate the body's metabolism and affect critical body functions, such as energy level and heart rate. The most stunning statistic is that up to 60% of those with thyroid disease are unaware of their condition and that women are five to eight times more likely than men to have thyroid problems. The World Health Organization (WHO) has identified iodine deficiency as the world's most prevalent, yet easily preventable, cause of brain damage. Consequences of iodine deficiency include physical and mental retardation, cretinism, endemic goiter, hypothyroidism, and poor outcomes in pregnancy. Hypothyroidism, a condition that occurs when the thyroid gland does not produce enough thyroid hormone, is the most common thyroid disease. Symptoms include fatigue, depression, forgetfulness, irregular menses, and weight gain. Treatment of hypothyroidism is usually with a synthetic form of thyroid hormone called “levothyroxine.” Another autoimmune disease affecting the thyroid is Hashimoto's thyroiditis. This is the most common cause of hypothyroidism in the US, affecting mostly women. Diagnosis is usually confirmed by symptoms suggesting thyroid under activity, positive anti-thyroid antibodies, and small goiter (thyroid enlargement) on physical examination. Patients with an elevated blood level of TSH and/or goiter are treated with thyroxin (T4).
Iodine deficiency is a major public health concern worldwide. The main factor responsible for iodine deficiency is a low dietary supply of iodine. Prevention and control efforts aim primarily at ensuring adequate iodine intake to maintain normal thyroid function. Increased iodine intake can be implemented through food fortification with iodine and/or iodine supplementation. Salt is the most commonly used vehicle since it is inexpensive and widely available. Salt iodization is relatively easy to implement, regulate, and monitor. The World Health Assembly adopted USI. The WHO recommends adding 20/40 mg of iodine per kg of salt to meet iodine requirements assuming that the average consumption of salt per capita is 10 g/day.
A study was done to analyze the current status of morphologic and functional thyroid abnormalities in a previously iodine-deficient area. It was a population-based the Study of Health in Pomerania comprised 4310 participants, aged 20–79 years. Thyroid function (thyrotropin TSH free triiodothyronine [FT3], and FT4) and serum autoantibodies to thyroperoxidase (TPOAb) were evaluated from blood samples. Thyroid structure and size were measured by ultrasound. Data from 3941 participants with no known thyroid disorders were analyzed. The median iodine urine excretion was 12.4 μg/dL. The rate of decreased serum TSH levels (<0.3 mIU/L) was 11.3%; 2.2% of participants had suppressed serum TSH levels (<0.1 mIU/L). The prevalence of subclinical hyperthyroidism was 1.8%, the prevalence of overt hyperthyroidism was 0.4%. Elevated TSH levels were found in 1.2% of individuals. Subclinical hypothyroidism was observed in 0.5%, overt hypothyroidism in 0.7% of the sample. Elevated TPOAb were detected in 7% of participants, 4.1% of participants had TPOAb >200 IU/mL. The prevalence of goiter was 35.9%. An inhomogeneous echo pattern was detected in 35.2% and nodules in 20.2% of participants. Diffuse autoimmune thyroiditis was diagnosed in 47 participants (1.2%). There are a number of thyroid disorders in this previously iodine-deficient region. Further, studies are required to investigate the change of thyroid disorders during iodine supplementation programs.
Thyroid diseases are common worldwide. In India too, there is a significant burden of thyroid diseases. According to a projection from various studies on thyroid disease, it has been estimated that about 42 million people in India suffer from thyroid diseases. Among the various varieties of hypothyroidism, congenital hypothyroidism is probably the most important. Studies from Mumbai have suggested that congenital hypothyroidism is common in India, the disease occurring in 1 of 2640 neonates, when compared with the worldwide average value of 1 in 3800 participants. Hypothyroidism can occur in childhood too. In a clinic-based study from Mumbai, of 800 children with thyroid disease, 79% had hypothyroidism. Among adult people in India, the prevalence of hypothyroidism has been recently studied. In this population-based study done in Cochin on 971 adult participants, the prevalence of hypothyroidism was 3.9%. In women, the prevalence was higher, at 11.4%, when compared with men, in whom the prevalence was 6.2%.
A study was done to know the prevalence of hypothyroidism and its association with anti-TPO antibodies among the adult seafood consuming population in Kerala. It was a hospital-based cross-sectional study involving 300 patients. 30.4% of participants had thyroid dysfunction, prevalence of hypothyroidism and subclinical hypothyroidism was 11.7% and 15%, respectively. Anti-TPO antibody was positive in 71.4% hypothyroid patients and 68.9% subclinical hypothyroid patients. There was a significant relation between hypothyroidism and anti-TPO antibody suggesting thyroid autoimmunity as a risk factor for hypothyroidism.
A cross-sectional study was done in tertiary care hospital in Kerala with 935 adults to identify the prevalence of undetected hypothyroidism and associated risk factors. The participants were tested for TSH value and anti-TPO titer. Of 935 participants, 157 had raised TSH (16.7%). Of the 44 (of 157) hypothyroid study participants who were tested, 42 (95.5%) shad raised antibody titers suggestive of autoimmune thyroiditis which is highly significant. The study showed an increased prevalence of undetected hypothyroidism in midlife (41–50 years of age) with higher prevalence in females (19.2%). Most of the participants who were tested for anti-TPO antibodies were found to be having raised anti-TPO antibody titer suggestive of autoimmune thyroiditis. It has been reported as one of the leading causes of hypothyroidism. There is a large and increasing number of undetected hypothyroidism in the population, affecting the well-being, work efficiency, and productivity of the community, despite iodine sufficiency. Hypothyroidism being an easily tested and treated condition, larger population-based screening studies need to be undertaken.,
The present study explored the prevalence of hypothyroidism in one of the northern districts of Kerala which is a coastal area. 9.6% of the population was found to be affected with hypothyroidism. Most of the participants were diagnosed for the first time during the study-related screening. It suggests the iceberg phenomenon associated with hypothyroidism is existing in the society. Participants who are on medication for hypothyroidism (21%) also showed higher TSH values. It reflects the need for accurate and updated treatment modalities for hypothyroidism.
The prevalence of hypothyroidism among women is striking conclusion from the current study. The study finding supports many other studies done in various parts of the country., A study done in Guwahati reveals that the higher prevalence of hypothyroidism was found among female gender against their counterpart, 42.27% versus 25%. The association between female gender and hypothyroidism was significant in the current study with an odds ratio of 1.791. A relative risk of 1.73 was reported between female gender and prevalence of hypothyroidism.
A hospital-based study done in North Kerala revealed a prevalence of hypothyroidism of 4.2% among adults and the prevalence in female versus male was 4.3% versus 4.05%.
The study participants constitute about only 0.04% of the total population of Kannur district per 2011 census data. Another limitation in this study regarding the estimation of iodine content of the iodized salt. The investigators presume that iodine content in the body is sufficient without testing iodine markers such as urinary iodine excretion. The mark of autoimmunity (anti-TPO) was not tested in the current study. Comorbidities comparison between normal and hypothyroidism patients have not done in the present study.
To summarize, the present study threw light on the prevalence of hypothyroidism among the adult population in one of the coastal districts in Kerala. The study revealed the prevalence of hypothyroidism, namely 9.6%
| Conclusion|| |
Hypothyroidism is a growing public health concern in India. India is now in postiodization era, where iodine depletion is replaced by iodine sufficiency. Even then, thyroid disorders are increasing, predominantly hypothyroidism. The prevalence of hypothyroidism is 9.6% and there is clear evidence of more prevalence among female against their counterpart.
The study was done in collaboration with a multispecialty hospital, Kannur. A team consists of surgeon, laboratory technicians, registered nurses, supporting staff, and public relation officer was worked hand in hand in the conduction of various camps.
Financial support and sponsorship
Aster MIMS Hospital, Kannur, Kerala.
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3]