Childhood height and body mass index were associated with risk of adult thyroid cancer in a large cohort study

Adolescent and mid-life diet and subsequent risk of thyroid cancer in the NIH-AARP diet and health study

Although thyroid cancer is suspected to have a nutritional etiology, prospective studies examining the relationship between diet and thyroid cancer are lacking. During 1996-1997, NIH-AARP Diet and Health Study participants, ages 51-72 years, completed a 37-item food frequency questionnaire about diet at ages 12-13 years (adolescence) and 10 years before baseline (mid-life). Over a median 10 years of follow-up, 325 individuals (143 men and 182 women) were diagnosed with thyroid cancer. Multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for intakes of foods and food groups comparing the highest to the lowest quartiles. Adolescent intakes of chicken/turkey (HR = 1.59, 95% CI: 0.97-2.60; ptrend  < 0.01) and sweet baked goods (HR = 1.59, 95% CI: 1.09-2.34; ptrend  = 0.04) were positively associated with thyroid cancer risk, while intake of butter/margarine was inversely associated with risk (HR = 0.64, 95% CI: 0.44-0.91; ptrend  < 0.02). Similar to adolescent diet, mid-life intake of sweet baked goods was nonsignificantly associated with an increased risk of thyroid cancer (HR = 1.39, 95% CI: 0.96-2.00; ptrend  = 0.11), but intake of butter/margarine was inversely associated with risk (HR = 0.66, 95% CI: 0.46-0.95; ptrend  = 0.03). Among men, higher adolescent consumption of canned tuna was positively associated with risk of thyroid cancer (HR = 1.69, 95% CI: 1.01-2.83; ptrend  = 0.03), and greater mid-life intake of broccoli was associated with a twofold increased risk (HR = 2.13, 95% CI: 1.13-3.99; ptrend  < 0.01). This large prospective study suggests that several components of the adolescent and mid-life diet, including iodine-rich foods and goitrogens, may influence thyroid cancer risk.

Genome-wide screen of DNA methylation identifies novel markers in childhood obesity

Epigenetic modifications have been highlighted in chronic non-communicable diseases. The aim of this study was to investigate genome-wide DNA methylation for the identification of methylation markers in obesity. With obese Chinese preschool children, we performed comprehensive DNA methylation profiling of gene promoters and CpG islands to determine the differentially methylated genes using methylated DNA immunoprecipitation followed by hybridization to the NimbleGen Human DNA Methylation 385K Promoter Plus CpG Island Microarray. We found that compared to lean children, 251 promoters and 575 CGIs were demethylated, and 141 promoters and 277 CGIs were hypermethylated in obese children, and their distribution on chromosomes was imbalanced, showing more promoters and CGIs with demethylation on chromosomes 3, 16, 17 and 19 and more differentially methylated promoters and CGIs on chromosome X compared with chromosome Y. Further analysis indicated that aberrant methylations occurred mostly in HCP promoters and promoter CGIs. Among the top 80 promoters and CGIs that had differentiated methylation between obese and lean children, nearly half have been previously studied, and almost all of them are involved in the pathogenesis of cancers that are associated with many organs. Furthermore, four genes (FZD7, PRLHR, EXOSC4, and EIF6) with differential promoter methylation were validated, and their associations with obesity must be clarified. In conclusion, this study represents the first effort to determine methylation markers in obese Chinese children, which has potential relevance for identifying markers that are useful in elucidating the mechanisms of obesity pathogenesis and its complications.

Association between height and thyroid cancer risk: a meta-analysis of prospective cohort studies

While several epidemiological studies have investigated the relationship between height and risk for thyroid cancer, the results were inconsistent. In the present study, a systematic review and meta-analysis of prospective cohort studies was conducted to assess the impact of height on thyroid cancer risk. Online databases were searched up to December 30, 2014, for prospective cohort studies on the association between height and thyroid cancer risk. Pooled relative risks (RRs) and 95% confidence intervals (CIs) were calculated using a random-effects model of meta-analysis. In all, 11 articles were included in this meta-analysis, including 15 prospective cohort studies, containing 6,695,593 participants and 7,062 cases of thyroid cancer. By comparing the highest versus the lowest categories of height, we reported that risk of thyroid cancer was increased with height in both men (summary RR = 1.40, 95%CI 1.09-1.78, p = 0.008) and women (summary RR = 1.54, 95%CI 1.30-1.83, p < 0.001). The summary RR of thyroid cancer per 5-cm increase in height was 1.16 (95%CI 1.09-1.23, p < 0.001). The results were similar among men (per 5-cm increase RR = 1.13, 95%CI 1.03-1.23, p = 0.011) and women (per 5-cm increase RR = 1.18, 95%CI 1.10-1.27, p < 0.001). No obvious risk of publication bias was observed. Our meta-analysis provides strong evidence for a dose-response relationship between height and risk of thyroid cancer in both men and women.

Obesity and risk of thyroid cancer: evidence from a meta-analysis of 21 observational studies

BACKGROUND

Several studies have evaluated the association between obesity and thyroid cancer risk. However, the results remain uncertain. In this study, we conducted a meta-analysis to assess the association between obesity and thyroid cancer risk.

MATERIAL/METHODS

Published literature from PubMed, EMBASE, Springer Link, Ovid, Chinese Wanfang Data Knowledge Service Platform, Chinese National Knowledge Infrastructure (CNKI), and Chinese Biology Medicine (CBM) were retrieved before 10 August 2014. We included all studies that reported adjusted risk ratios (RRs), hazard ratios (HRs) or odds ratios (ORs), and 95% confidence intervals (CIs) of thyroid cancer risk.

RESULTS

Thirty-two studies (n=12 620 676) were included in this meta-analysis. Obesity was associated with a significantly increased risk of thyroid cancer (adjusted RR=1.33; 95% CI, 1.24-1.42; I2=25%). In the subgroup analysis by study type, increased risk of thyroid cancer was found in cohort studies and case-control studies. In subgroup analysis by sex, both obese men and women were at significantly greater risk of thyroid cancer than non-obese subjects. When stratified by ethnicity, significantly elevated risk was observed in Caucasians and in Asians. In the age subgroup analysis, both young and old populations showed increased thyroid cancer risk. Subgroup analysis on smoking status showed that increased thyroid cancer risks were found in smokers and in non-smokers. In the histology subgroup analyses, increased risks of papillary thyroid cancer, follicular thyroid cancer, and anaplastic thyroid cancer were observed. However, obesity was associated with decreased risk of medullary thyroid cancer.

CONCLUSIONS

Our results indicate that obesity is associated with an increased thyroid cancer risk, except medullary thyroid cancer.

Meta-analysis in the association between obesity and risk of thyroid cancer

Although many epidemiologic studies have investigated obesity and thyroid cancer risk, definite conclusions cannot be drawn. To clarify the effects of obesity on the risk of thyroid cancer, a meta-analysis was performed. Related studies were identified from PubMed, Springer Link, Ovid, Chinese Wanfang Data Knowledge Service Platform, Chinese National Knowledge Infrastructure (CNKI), and Chinese Biology Medicine (CBM) till 16 Aug 2014. Pooled RRs and 95% CIs were used to assess the strength of the associations. A total of 16 studies including 12616154 subjects were involved in this meta-analysis. A significantly elevated thyroid cancer risk was found in overall analysis (RR = 1.29, 95% CI 1.20-1.37, P < 0.00001). In the gender subgroup analyses, a statistically significant association was found in male patients (RR = 1.35, 95% CI 1.16-1.58, P = 0.0001) and in female patients (RR = 1.29, 95% CI 1.19-1.40, P < 0.00001). When we limited the meta-analysis to studies that controlled for age (RR = 1.34, 95% CI 1.24-1.44, P < 0.00001), smoke (RR = 1.36, 95% CI 1.22-1.52, P < 0.00001), alcohol use (RR = 1.40, 95% CI 1.15-1.71, P = 0.0009), and history of benign thyroid disease (RR = 1.51, 95% CI 1.24-1.83, P < 0.0001), a significant association between obesity and thyroid cancer risk remained. This meta-analysis provides the evidence that obesity may contribute to the thyroid cancer development.

The association of the 'additional height index' with atopic diseases, non-atopic asthma, ischaemic heart disease and mortality: a population-based study

OBJECTIVE

Intrauterine growth has been associated with atopic conditions. Growth and adult height have been associated with cardiovascular disease, cancers and mortality but are highly genetic traits. The objectives of the study were as follows: first, to define a height measure indicating an individual's height below or above that which could be expected based on parental height (genetic inheritance) and growth charts. It was named 'the additional height index' (AHI), defined as (attained-expected) height; second, to investigate possible associations of AHI with atopic versus non-atopic health outcomes and with ischaemic heart disease (IHD) and IHD mortality.

DESIGN

General population-based study.

SETTING

Research centre.

PARTICIPANTS

A random sample of 2656 men and women living in greater Copenhagen took part in the MONICA10 study (the Danish monitoring trends and determinants of cardiovascular disease). In total, 1900 participants with information of parental height were selected.

OUTCOME MEASURES

Atopic sensitisation (serum IgE), questionnaire information of atopic dermatitis, rhinoconjunctivitis, asthma or wheezing, and registry-based diagnoses of IHD/IHD mortality from National Registries.

RESULTS

Increasing levels of AHI were inversely associated with non-atopic asthma, non-atopic wheezing, IHD and IHD mortality (IHD-all). For one SD increase of AHI, the OR or HR with CI in adjusted analyses was non-atopic asthma OR=0.52 (0.36 to 0.74), non-atopic wheezing OR=0.67 (0.51 to 0.89), and IHD-all HR=0.89 (0.78 to 1.01). The level of AHI was higher among individuals with atopic dermatitis, allergic rhinoconjunctivitis and atopic sensitisation (all p values <0.001) compared with individuals without those conditions; however, the associations were not confirmed in adjusted analyses.

CONCLUSIONS

Individuals with childhood conditions that led them to attain tallness higher than expected from their parents' height may be at lower risk of non-atopic asthma/wheeze and IHD/IHD mortality but possibly at higher risk of atopic conditions. The measure of tallness below or above the expected height could be a sensitive alternative to normal height in epidemiological analyses.