Epidemiology of Thyroid Disorders

Jahangir Moini, Katherine Pereira, Mohtashem Samsam

• Publisher: Elsevier
• Year: 2020
• Print ISBN:
  9780128185001
• eBook ISBN:
  9780128182741
• Topic: Medicine
• Subtopic: Endocrinology & Metabolism

Epidemiology of Thyroid Disorders provides comprehensive, clinical knowledge to professionals dealing with thyroid disorders. The book focuses on the pathophysiology of thyroid disorders, the prevalence and incidence of various diseases, and their prevention. This focused analysis on thyroid disorders raises awareness of this global problem that, once diagnosed or misdiagnosed, can sometimes lead to over-treatment and cardiovascular complications, especially in the elderly. This succinct, targeted reference gives the reader excellent information on the epidemiology of global thyroid disorders, as well as up-to-date treatment data and a special focus on prevention. - Serves as a starting point for medical professionals, addressing the patterns, risk factors, prevention, and treatment of thyroid disorders around the world - Discusses the prevalence of thyroid disorders around the world, covering disability and cost burden - Covers recent trends, technologies and advancements in the management of thyroid diseases

Part I

Principles and concepts

Outline

• Chapter 1 Global epidemiology of thyroid disorders
• Chapter 2 Structures and functions of the thyroid gland
• Chapter 3 Iodine and thyroid hormones

Chapter 1

Global epidemiology of thyroid disorders

Abstract

Thyroid disorders are very common throughout the world and cause problems because of overfunctioning or underfunctioning of the thyroid gland. These disorders may lead to enlargement of the thyroid gland, causing direct symptoms such as difficulty in swallowing and neck discomfort. With today’s increased elderly population and better diagnostic methods, thyroid disorders are documented more often. The most significant problem related to thyroid is global iodine deficiency, which results in goiter and hypothyroidism. Thyroid disorders affect people of all ages and are more common in females than males. The highest incidence of overt hyperthyroidism is in people more than the age of 65. Hashimoto’s thyroiditis is the most common type of thyroiditis. Graves’ disease is an autoimmune disorder, which is eight times more prevalent in females and twice as common in African Americans as in other groups. More than 75% of thyroid cancers occur in females between ages 20 and 55. In this chapter the focuses are on the incidence and prevalence of thyroid disorders throughout the global population.

Key terms

adenomas; age-specific death rates; celiac disease; endemic goiter; goiter; Graves’ disease; Hashimoto’s thyroiditis; hyperthyroidism; hyperthyrotropinemia; hypothyroidism; hypothyroxinemia; iodization; life expectancy; selenium; thyroid cancer; thyroid nodules; thyroid storm; thyroperoxidase

Contents

Outline

• World population 3
• Aging of the population 4
• Life expectancy 6
• Distribution of thyroid disorders by gender and age 8
• Population-based models of thyroid disorders 10
• Global prevalence of thyroid disorders 11
• Global epidemiology of thyroid disorders 12
• Global prevention of thyroid disorders 12
• Global death rates from thyroid disorders 15
• Disability-adjusted life years for thyroid disorders 17
• Burden of thyroid disorders 18
• Further reading 18

Thyroid disorders are very common throughout the world and cause problems because of overfunctioning or underfunctioning of the thyroid gland. These disorders may lead to enlargement of the thyroid gland, causing direct symptoms such as difficulty in swallowing and neck discomfort. With today’s increased elderly population and better diagnostic methods, thyroid disorders are documented more often. The most significant problem related to thyroid is global iodine deficiency, which results in goiter and hypothyroidism. Thyroid disorders affect people of all ages and are more common in females than males. The highest incidence of overt hyperthyroidism is in people more than the age of 65. Hashimoto’s thyroiditis is the most common type of thyroiditis. Graves’ disease is an autoimmune disorder, which is eight times more prevalent in females and twice as common in African Americans as in other groups. More than 75% of thyroid cancers occur in females between ages 20 and 55. In this chapter the focuses are on the incidence and prevalence of thyroid disorders throughout the global population.

World population

Currently, the world population is growing at a rate of approximately 1.07% per year. The current average population increase is estimated to be 82 million people annually. The peak annual growth rate was during the late 1960s, when it was about 2% per year. It is estimated to continue decreasing annually, reaching only 1% growth by the year 2023. World population doubled between the years 1959 and 1999. Even with the reduction in annual increases, the United Nations projects that the world population will reach 10 billion by the year 2056. This data comes from many sources, including the United Nations Population Division, the World Population Prospect, and the International Programs Center at the United States Census Bureau. As of May 2019, census bureaus throughout various countries have estimated that the world population presently exceeds 7.7 billion people. The top 10 most populated countries are as follows:

• • China (1.4 billion)
• • India (1.3 billion)
• • United States (328 million)
• • Indonesia (269 million)
• • Brazil (212 million)
• • Pakistan (203 million)
• • Nigeria (200 million)
• • Bangladesh (167 million)
• • Russia (143 million)
• • Mexico (132 million)

Aging of the population

The world population is also increasing in age. There are two primary reasons for this. The first is that we are simply living longer due to healthier lifestyles and better medical treatments. The second is that the fertility rate is decreasing, resulting in fewer women becoming pregnant. The average life expectancy in the United States is higher today than during any other time in history. The United Nations issued a report showing that people ages 65 years and older increased from 8% of the total population in 1950 to 12% of the total population in 2000. This figure is expected to increase to 20% by the year 2050 and will probably rise steadily after that. This is primarily due to large improvements in health care, investment in medical research, and better health insurance availability. Fewer Americans are dying from diseases, such as breast cancer, colon cancer, prostate cancer, heart disease, and HIV.

According to the World Health Organization, the global population is similarly increasing in age. There will soon be higher numbers of elderly people than children, and more people at extreme old age than ever in history (see Fig. 1.1). To understand this phenomenon, we must realize that in 1900, the major health threats were infectious and parasitic diseases. These often caused the deaths of infants and children. Today, noncommunicable diseases that mostly affect adults and the elderly have the greatest impact on global health. The health and economic burdens of age-related disability can be affected by environmental factors that determine if people can remain independent, even though they may be physically limited. The longer people remain mobile and take care of themselves, the lower the costs will be for required long-term care.

Figure 1.1 Changes in age of the global population since 1950. https://www.nia.nih.gov/sites/default/files/2017-06/global_health_aging.pdf.

The facts about decreasing fertility, on a global basis, are also very important to understand. In more developed countries, fertility fell below the “replacement” rate of two live births per woman in the 1970s, while women in the 1950s averaged three live births. In less developed countries, fertility rates fell even faster. In 1950 women in these countries averaged six live births, but by 2006, the rate was at or below two live births. While Niger, an African country, has the highest fertility rate, of 7.1 children per woman, many countries with large populations are now toward the lower end of the scale. For example, the United States now ranks 135th on the list with 1.8 children per woman. The lowest fertility rate is in Taiwan with 1.2 children per woman, followed by Moldova, Portugal, Singapore, Poland, Greece, South Korea, Hong Kong, Cyprus, and Macau.

Countries that are rapidly “shrinking” in population include Ukraine, which will decrease 22% by 2050. Poland, the Russian Federation, Italy, and Spain are also shrinking. The population of the European Union is expected to peak by 2050 and then gradually decline. Germany has experienced demographic decline for more than a generation and is estimated to drop 7.7% in population by 2050, not taking into account the recent immigration into the country. Bulgaria is expected to shrink 27% by 2050, and Romania will shrink by 22%. Japan will have a decrease in population by 15% and by 2030 will actually have more people more than 80 years than below 15 years. China’s extremely low fertility rate means that the country will have 28 million less people by 2050.

Focus on aging and th...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Dedication
• About the authors
• Preface
• Acknowledgment
• Part I: Principles and concepts
• Part II: Thyroid dysfunction and clinical application
• Part III: Special populations
• Glossary
• Index