The Association between Selenium and Other Micronutrients and Thyroid Cancer Incidence in the NIH-AARP Diet and Health Study

Abstract

BackgroundSelenium is an essential trace element that is important for thyroid hormone metabolism and has antioxidant properties which protect the thyroid gland from oxidative stress. The association of selenium, as well as intake of other micronutrients, with thyroid cancer is unclear.MethodsWe evaluated associations of dietary selenium, beta-carotene, calcium, vitamin D, vitamin C, vitamin E, folate, magnesium, and zinc intake with thyroid cancer risk in the National Institutes of Health – American Association of Retired Persons Diet and Health Study, a large prospective cohort of 566,398 men and women aged 50–71 years in 1995–1996. Multivariable-adjusted Cox proportional hazards regression was used to examine associations between dietary intake of micronutrients, assessed using a food frequency questionnaire, and thyroid cancer cases, ascertained by linkage to state cancer registries and the National Death Index.ResultsWith the exception of vitamin C, which was associated with an increased risk of thyroid cancer (HRQ5 vs Q1, 1.34; 95% CI, 1.02–1.76; Ptrend, <0.01), we observed no evidence of an association between quintile of selenium (HRQ5 vs Q1, 1.23; 95% CI, 0.92–1.65; Ptrend, 0.26) or other micronutrient intake and thyroid cancer.ConclusionOur study does not suggest strong evidence for an association between dietary intake of selenium or other micronutrients and thyroid cancer risk. More studies are needed to clarify the role of selenium and other micronutrients in thyroid carcinogenesis.

Consumption of fruits, vegetables and fruit juices and differentiated thyroid carcinoma risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) study

“…Moreover, a deficiency in magnesium may be involved in the aetiology of some thyroid diseases . However the protective effects of F&V and fruit juices components are not consistent and several studies showed null results, or even positive associations ( e.g ., with beta‐carotene, vitamin C and flavanones) …”

The role of selenium in thyroid gland pathophysiology

“…In many studies on animal models, as well as in epidemiological and interventional surveys, beneficial effects were confirmed of normal or even increased serum selenium concentrations on the initiation, progression, and even metastases of various cancer types but not of thyroid cancer [50,102]. The relationship between selenium supplementation and the incidence of thyroid cancer has been verified in many clinical studies (Table I); however, it has not been unequivocally confirmed, especially in the Polish population [103][104][105][106][107][108][109][110][111]. The access to mainly retrospective data, the relatively small groups of patients, and the short observation periods, as well as only single assays of selenium concentration levels, were all significant limitations in the performed studies.…”

“…W wielu badaniach na modelach zwierzęcych oraz epidemiologicznych i interwencyjnych stwierdzono korzystny wpływ prawidłowych, a nawet podwyższonych stężeń selenu w surowicy na inicjację, progresję, a nawet przerzuty różnych rodzajów nowotworów, ale nie raka tarczycy [50,102]. Związek pomiędzy zaopatrzeniem w selen i występowaniem raka tarczycy został zweryfikowany w wielu badaniach klinicznych (Tabela I) i w metaanalizie, jednakże nie został jednoznacznie potwierdzony, zwłaszcza w polskiej populacji [103][104][105][106][107][108][109][110][111]. Dostęp głównie do danych retrospektywnych, relatywnie małe grupy pacjentów i krótki czas obserwacji oraz pojedyncze oznaczenia zaopatrzenia w selen stanowią istotne ograniczenia przeprowadzonych badań.…”

The crosstalk between trace elements with DNA damage response, repair, and oxidative stress in cancer

“…25,52,53 Results from human clinical intervention trials support that Se may have chemopreventive effects on lung cancer, especially for subjects with low Se status. 54,55 Although Se is necessary for the metabolism of thyroid hormones and plays an important role in the protection of thyroid gland from OS, 56,57 no strong association has been found between dietary intake of Se and the incidence of thyroid cancer. 57 Similarly, it has also been reported that Se supplementation has no effect on the reduction of bladder cancer incidence, and cannot prevent the recurrence of bladder cancer.…”