Prevalence and concentration of Aflatoxin M1 in human breast milk in sub-Saharan Africa: a systematic review and meta-analysis, and cancer risk assessment

The current and future global burden of cancer among adolescents and young adults: a population-based study

BACKGROUND

Compared with children and older adults, the burden of cancer in adolescents and young adults (ages 15-39) is understudied. We aimed to quantify the global burden of adolescent and young adult cancer in 2022 and 2050, and explore patterns in incidence, mortality, and case fatality.

METHODS

In this population-based study, we used the GLOBOCAN database to quantify the number of new cases and cancer-related deaths, and corresponding age-standardised incidence and mortality rates (ASRs; per 100 000 people aged 15-39 years), in adolescents and young adults. Estimates were quantified for all cancers combined, excluding non-melanoma skin cancer, and 33 specific cancer types. Case fatality was estimated using mortality-to-incidence ratios. Overall and sex-specific estimates were calculated at the world, regional, human development index (HDI), and income level. We estimated the future cancer burden by applying the GLOBOCAN 2022 rates to sex-specific demographic projections for the year 2050 using the UN World Population Prospects 2019 revision.

FINDINGS

An estimated 1 300 196 cases and 377 621 cancer-related deaths occurred in adolescents and young adults in 2022. Incidence ASRs were 1·9-times higher and mortality ASRs were 1·2-times higher in females than in males (incidence ASR 52·9 vs 28·3; mortality ASR 13·1 vs 10·6). Although the incidence ASR was highest in the high-income countries, the mortality ASR was highest in the low-income countries; as a result, case fatality ranged from 12% in high-income settings to 57% in low-income settings. Of the 33 cancer types included in our analyses, breast or cervical cancer was the most frequently diagnosed cancer and cause of cancer-related death in 163 and 93 countries, respectively; incidence and mortality also varied the most by region for these cancers. Finally, the adolescent and young adult cancer burden globally is projected to increase by about 12% from 2022 to 2050, albeit with declines of 10·7% projected in very high HDI countries. The increase is expected to overwhelmingly impact low HDI settings, where the burden of both cancer cases and deaths is projected to double (a 102·3% increase).

INTERPRETATION

Although the adolescent and young adult cancer burden incidence is highest in the most developed settings, transitioning countries have the poorest outcomes and will face the greatest increases in burden by 2050. These findings act as a reference to the global adolescent and young adult cancer community to inform cancer control priorities and decrease global inequities.

FUNDING

None.

Aflatoxin M1 in milk and dairy products: The state of the evidence for child growth impairment

Aflatoxin M1 (AFM1) is a metabolite of the more toxic aflatoxin B1 (AFB1) a mycotoxin produced by the fungi Aspergillus flavus and A. parasiticus; which contaminates maize, peanuts, tree nuts, and oilseeds, among other crops in warm regions of the world. When mammals consume AFB1 in these foods, they secrete AFM1 in milk. A recent analysis indicated negligible cancer risk associated with AFM1 exposure, but whether AFM1 impairs children's growth is important to understand because children consume relatively more milk than adults worldwide. Our paper reviews the evidence on the link between AFM1 exposure and child growth impairment. We find that the existing studies are contradictory and necessitates further studies on this question; in particular, those that control for potentially confounding factors such as household socioeconomic status, children's overall diets, hygienic factors, and agroecological zone. Though many nations have policies for maximum AFM1 limits in dairy foods, they are not based on an explicit health risk analysis of AFM1 but on conversion rates of AFB1 levels to AFM1 in dairy products. Future studies on AFM1's potential harmful effects on child growth will help to better inform policies on maximum allowable AFM1 in milk and other dairy products.

Omics analysis revealed the intestinal toxicity induced by aflatoxin B1 and aflatoxin M1

Aflatoxin B1 (AFB1), a common mycotoxin, can occur in agricultural products. As a metabolite of AFB1, aflatoxin M1 (AFM1) mainly exist in dairy products. These two mycotoxins threaten human health, although it is unclear how they affect the function of the intestinal barrier. In this study, mice were exposed to AFB1 (0.3 mg/kg body b.w.) and AFM1(3.0 mg/kg b.w.) either individually or in combination for 28 days to explore the main differentially expressed proteins (DEPs) and the associated enriched pathways. These findings were preliminarily verified by the transcriptomic and proteomic analyses in differentiated Caco-2 cells. The results revealed that AFB1 and AFM1 exposure in mice disrupted the function of the intestinal barrier, and the combined toxicity was greater than that of each toxin alone. Further proteomic analysis in mice demonstrated that the mechanisms underlying these differences could be explained as follows: (i) lipid metabolism was enriched by AFB1-induced DEPs. (ii) protein export pathway was stimulated by AFM1-induced DEPs. (iii) cell metabolic ability was inhibited (as evidenced by changes in UDP-GT1, UDP-GT2, and Gatm6), apoptosis was induced (MAP4K3), and epithelial cell integrity was disrupted (Claudin7 and IQGAP2), resulting in more extensive intestinal damage after combined treatment. In conclusion, the hazardous impact of co-exposure to AFB1 and AFM1 from proteomic perspectives was demonstrated in the present study.

A systematic review and meta-analysis of pollutants in environmental media

Environmental pollutants are ubiquitous in our environmental media, resulting in detrimental impacts on both humans and the environment. An evidence-based review, particularly a systematic review and meta-analysis, performs a crucial function in assessing the pollution status of pollutants in environmental media at national and global scales. We selected and thoroughly investigated 76 papers focusing on systematic reviews and meta-analyses of contaminants in environmental media. The need to broaden the scope of studies was observed with an increase in the total number of publications, and there were greater focuses on food safety, water pollution, biological pollution, and environmental risks. Furthermore, this review outlined the fundamental procedures involved in a systematic review and meta-analysis, including literature searching, screening of articles, study quality analysis, data extraction and synthesis, and meta-analysis. A meta-analysis typically comprises fixed- and/or random-effects meta-analysis, identifying and measuring heterogeneity, sensitivity analysis, publication bias, subgroup analysis, and meta-regression. We specifically explored the application of meta-analysis to assess the presence of contaminants in environmental media based on two different pollutant categories, namely, non-biological and biological pollutants. The mean value is commonly utilized to assess the pooled concentration of non-biological pollutants, while the prevalence serves as the effect size of biological pollutants. Additionally, we summarized the innovative applications, frequent misuses, and problems encountered in systematic reviews and meta-analyses. Finally, we proposed several suggestions for future research endeavors.

Incidence of aflatoxin M1 in cows' milk in Pakistan, effects on milk quality and evaluation of therapeutic management in dairy animals

The present study was aimed at measuring the concentration of aflatoxin M1 (AFM1) in the milk of Holstein Friesian cows, its effect on the milk quality and seasonal trends, as well as to investigate the efficacy of a commercial clay-based toxin binder. For this purpose, milk samples from dairy cows (n = 72) were collected and assayed for AFM1 before employing a clay-based toxin binder. The milk samples (n = 72) were collected from selected animals, revealing that 69.4% of the milk samples had AFM1 levels above the United States permissible limit (0.5 μg/kg). The incidence of AFM1 in milk during the winter and summer was 82.5% and 53.1%, respectively. Owing to the presence of AFM1, the level of milk fat, solids-not-fat, and protein were found to be low. Subsequently, the affected animals were divided into two groups, i.e., AFM1 positive control (n = 10) and the experimental group (n = 40). The experimental group of animals were fed the clay-based toxin binder at 25 g/animal/day. A progressive decrease of 19.8% in the AFM1 levels was observed on day 4 and on day 7 (53.6%) in the treatment group. Furthermore, the fat, solids-non-fat and protein increased significantly in the milk. In conclusion, a high level of AFM1 contamination occurs in the milk in Pakistan, affecting the quality of the milk production. Clay-based toxin binders may be used to ensure the milk quality and to protect the animal and consumer health.

The Role of Cow's Milk Consumption in Breast Cancer Initiation and Progression

PURPOSE OF REVIEW

This review evaluates cow milk's impact on breast carcinogenesis by linking recent epidemiological evidence and new insights into the molecular signaling of milk and its constituents in breast cancer (BCa) pathogenesis.

RECENT FINDINGS

Recent prospective cohort studies support the association between cow's milk consumption and the risk of estrogen receptor-α-positive (ER+) BCa. Milk is a complex biological fluid that increases systemic insulin-like growth factor 1 (IGF-1), insulin and estrogen signaling, and interacting hormonal promoters of BCa. Further potential oncogenic components of commercial milk include exosomal microRNAs (miR-148a-3p, miR-21-5p), bovine meat and milk factors, aflatoxin M1, bisphenol A, pesticides, and micro- and nanoplastics. Individuals with BRCA1 loss-of-function mutations and FTO and IGF1 gain-of-function polymorphisms enhancing IGF-1/mTORC1 signaling may be at increased risk for milk-induced ER+ BCa. Recent prospective epidemiological and pathobiochemical studies identify commercial milk consumption as a critical risk factor of ER+ BCa. Large meta-analyses gathering individuals of different ethnic origins with milk derived from dairy cows of varying genetic backgrounds and diverse feeding procedures as well as missing data on thermal processing of milk (pasteurization versus ultra-heat treatment) make multi-national meta-analyses unsuitable for BCa risk estimations in susceptible populations. Future studies are required that consider all vulnerable periods of breast carcinogenesis to cow's milk exposure, beginning during the perinatal period and puberty, since these are the most critical periods of mammary gland morphogenesis. Notwithstanding the need for better studies including detailed information on milk processing and vulnerable periods of human breast carcinogenesis, the available evidence suggests that dietary guidelines on milk consumption may have to be reconsidered.