Abstract
Based on these facts, the World Health Assembly (WHA) passed resolution WHA 43.2 calling upon the World Health Organization (WHO) to aim at eliminating ID as a public health problem; this goal was reaffirmed in resolution WHA 49.13.2010 (3). This objective is particularly pressing since, although ID is the main cause of endemic goiter and hypothyroidism, additional environmental factors, such as selenium and iron deficiency, pollution, stress, smoking, and obesity, are increasingly involved in the pathogenesis of TDs. These are further compounded by a multiplicity of genetic factors.
In areas with iodine sufficiency, autoimmune thyroiditis (goitrous or atrophic) is the prevalent form of TDs (4). As already noted, the global prevalence of most TDs, thyroid cancer included, is increasing alarmingly and is anticipated to rise further over the next few decades. Thyroid cancer deserves special mention because it has had a dramatic increase of 89% in the past decade. This is partially due to improved and widely applied diagnostic modalities such as ultrasound, fine-needle aspiration, and magnetic resonance imaging (MRI). The majority of cases of thyroid cancer are curable, although 5%–10% of patients succumb to the disease. Various environmental factors have been implicated. These include smoking, for example, which may promote nodular goiter. Obesity, though its prevalence has not increased during the last 10 years, is very common, with 35.5% of adult men and 35.8% of adult women being affected (5). Notably, it has been reported that in both men and women body mass index is positively associated with the risk of thyroid cancer. Thus obesity is likely an independent risk factor for thyroid cancer (6).
Chronic noncommunicable diseases (NCDs; e.g., cardiovascular disease, cancer, chronic respiratory disease, diabetes) have been defined as diseases that affect individuals over a broad period of time and for which there are no known causative agents that transmit the condition to others. NCDs are the commonest causes of mortality and premature death around the world, while also inflicting high rates of disability in those affected. The death toll from these diseases is mounting steeply, numbering 36 million of the 57 million people who died in 2008, thus prompting the Director of the WHO, at the last general assembly, to characterize noncommunicable disease as a “slow-motion disaster” (7). And yet, though their increase is projected to entail an immense adverse economic impact in the coming decades ($47 trillion by 2030), in many countries they are preventable, in large measure by using well-structured behavioral, pharmaceutical, and other interventions (8).
Despite this encouraging recognition that awareness and timely intervention can preclude serious complications, it is still poorly recognized that many TDs promote the disturbing characteristics of other NCDs, a relationship that is even more unfortunate because of their dramatic increase over the past decade. Today, for example, between 27 and 60 million Americans are believed to have latent or overt TDs. Some of the consequences of certain TDs are detrimental effects on blood pressure, exacerbation of insulin resistance, and atrial fibrillation. In addition, TDs are frequently encountered and likely worsen other causes of dyslipidemia and cases of atherosclerosis and diabetes mellitus. Even the subclinical forms of hypo- or hyperthyroidism may have an impact on cardiac contractility, diastolic function, heart rate, rhythm, cardiac mass, and quality of life (9). Patients, especially postmenopausal women, with overt as well as subclinical hyperthyroidism, often have low bone mass density, thus exposing them to an increased risk of bone fractures, joint disorders, and age-related loss of stature. In addition, TDs in pregnant women, even in their subclinical forms, may adversely influence the outcome of pregnancy by amplifying the risk of miscarriage and impairing fetal development (10,11).
It is noteworthy that many TDs share key risk factors with NCDs; e.g., unhealthful lifestyle, a qualitatively poor diet combined with chronic past exposure, these enhancing the current burden of disease, while the future burden of disease is determined, in both TDs and NCDs, by current exposure and practices (12). Despite this, there is no policy of the WHO, other than that relating to ID, to deal with the specific consequences of TDs and the upsurge in their incidence. In a world with ever-increasing globalization, with expectations of better health falling far short of desirable and appropriate goals, especially in developing countries, a major effort to counteract the tide of TDs and other NCDs is mandatory (13 –15).
Taking all of these factors into account we propose an initiative to encourage and lobby the WHO to include TDs as a distinct member of the group of NCDs, thereby enhancing their prevention and management.