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1.
PLOS Glob Public Health ; 3(10): e0002432, 2023.
Article de Anglais | MEDLINE | ID: mdl-37874786

RÉSUMÉ

The South African Breast Cancer and HIV Outcomes prospective cohort (SABCHO) study was established to investigate survival determinants among HIV-positive and HIV-negative SA women with breast cancer. This paper describes common and unique characteristics of the cancer centres and their participants, examining disparities in pathways to diagnosis, treatment resources and approaches adopted to mitigate resource constraints. The Johannesburg (Jhb), Soweto (Sow), and Durban (Dbn) sites treat mainly urban, relatively better educated and more socioeconomically advantaged patients whereas the Pietermaritzburg (Pmb) and Empangeni (Emp) sites treat predominantly rural, less educated and more impoverished communities The Sow, Jhb, and Emp sites had relatively younger patients (mean ages 54 ±14.5, 55±13.7 and 54±14.3 respectively), whereas patients at the Dbn and Pmb sites, with greater representation of Asian Indian women, were relatively older (mean age 57 ±13.9 and 58 ±14.6 respectively). HIV prevalence among the cohort was high, ranging from 15%-42%, (Cohort obesity (BMI ≥ 30 kg/m2) at 60%, self-reported hypertension (41%) and diabetes (13%). Direct referral of patients from primary care clinics to cancer centre occurred only at the Sow site which uniquely ran an open clinic and where early stage (I and II) proportions were highest at 48.5%. The other sites relied on indirect patient referral from regional hospitals where significant delays in diagnostics occurred and early-stage proportions were a low (15%- 37.3%). The Emp site referred patients for all treatments to the Dbn site located 200km away; the Sow site provided surgery and endocrine treatment services but referred patients to the Jhb site 30 Km away for chemo- and radiation therapy. The Jhb, Dbn and Pmb sites all provided complete oncology treatment services. All treatment centres followed international guidelines for their treatment approaches. Findings may inform policy interventions to address national and regional disparities in breast cancer care.

2.
PLoS One ; 18(2): e0281916, 2023.
Article de Anglais | MEDLINE | ID: mdl-36795733

RÉSUMÉ

OBJECTIVE: In low- and middle-income countries (LMICs), advanced-stage diagnosis of breast cancer (BC) is common, and this contributes to poor survival. Understanding the determinants of the stage at diagnosis will aid in designing interventions to downstage disease and improve survival from BC in LMICs. METHODS: Within the South African Breast Cancers and HIV Outcomes (SABCHO) cohort, we examined factors affecting the stage at diagnosis of histologically confirmed invasive breast cancer at five tertiary hospitals in South Africa (SA). The stage was assessed clinically. To examine the associations of the modifiable health system, socio-economic/household and non-modifiable individual factors, hierarchical multivariable logistic regression with odds of late-stage at diagnosis (stage III-IV), was used. RESULTS: The majority (59%) of the included 3497 women were diagnosed with late-stage BC disease. The effect of health system-level factors on late-stage BC diagnosis was consistent and significant even when adjusted for both socio-economic- and individual-level factors. Women diagnosed in a tertiary hospital that predominantly serves a rural population were 3 times (OR = 2.89 (95% CI: 1.40-5.97) as likely to be associated with late-stage BC diagnosis when compared to those diagnosed at a hospital that predominantly serves an urban population. Taking more than 3 months from identifying the BC problem to the first health system entry (OR = 1.66 (95% CI: 1.38-2.00)), and having luminal B (OR = 1.49 (95% CI: 1.19-1.87)) or HER2-enriched (OR = 1.64 (95% CI: 1.16-2.32)) molecular subtype as compared to luminal A, were associated with a late-stage diagnosis. Whilst having a higher socio-economic level (a wealth index of 5) reduced the probability of late-stage BC at diagnosis, (OR = 0.64 (95% CI: 0.47-0.85)). CONCLUSION: Advanced-stage diagnosis of BC among women in SA who access health services through the public health system was associated with both modifiable health system-level factors and non-modifiable individual-level factors. These may be considered as elements in interventions to reduce the time to diagnosis of breast cancer in women.


Sujet(s)
Tumeurs du sein , Infections à VIH , Disparités d'accès aux soins , Femelle , Humains , , Tumeurs du sein/diagnostic , Tumeurs du sein/épidémiologie , Infections à VIH/diagnostic , Infections à VIH/épidémiologie , Infections à VIH/anatomopathologie , Stadification tumorale , République d'Afrique du Sud/épidémiologie
3.
Int J Cancer ; 148(9): 2158-2170, 2021 05 01.
Article de Anglais | MEDLINE | ID: mdl-33180326

RÉSUMÉ

The presence of preexisting morbidities poses a challenge to cancer patient care. There is little information on the profile and prevalence of multi-morbidities in breast cancer patients across middle income countries (MIC) to lower income countries (LIC) in sub-Saharan Africa (SSA). The African Breast Cancer-Disparities in Outcomes (ABC-DO) breast cancer cohort spans upper MICs South Africa and Namibia, lower MICs Zambia and Nigeria and LIC Uganda. At cancer diagnosis, seven morbidities were assessed: obesity, hypertension, diabetes, asthma/chronic obstructive pulmonary disease, heart disease, tuberculosis and HIV. Logistic regression models were used to assess determinants of morbidities and the influence of morbidities on advanced stage (stage III/IV) breast cancer diagnosis. Among 2189 women, morbidity prevalence was the highest for obesity (35%, country-specific range 15-57%), hypertension (32%, 15-51%) and HIV (16%, 2-26%) then for diabetes (7%, 4%-10%), asthma (4%, 2%-10%), tuberculosis (4%, 0%-8%) and heart disease (3%, 1%-7%). Obesity and hypertension were more common in upper MICs and in higher socioeconomic groups. Overall, 27% of women had at least two preexisting morbidities. Older women were more likely to have obesity (odds ratio: 1.09 per 10 years, 95% CI 1.01-1.18), hypertension (1.98, 1.81-2.17), diabetes (1.51, 1.32-1.74) and heart disease (1.69, 1.37-2.09) and were less likely to be HIV positive (0.64, 0.58-0.71). Multi-morbidity was not associated with stage at diagnosis, with the exception of earlier stage in obese and hypertensive women. Breast cancer patients in higher income countries and higher social groups in SSA face the additional burden of preexisting non-communicable diseases, particularly obesity and hypertension, exacerbated by HIV in Southern/Eastern Africa.


Sujet(s)
Tumeurs du sein/épidémiologie , Afrique subsaharienne , Tumeurs du sein/mortalité , Femelle , Disparités d'accès aux soins , Humains , , Analyse de survie
4.
Environ Geochem Health ; 42(4): 1047-1056, 2020 Apr.
Article de Anglais | MEDLINE | ID: mdl-31054071

RÉSUMÉ

Primary prevention is a key strategy to reducing the global burden of cancer, a disease responsible for ~ 9.6 million deaths per year and predicted to top 13 million by 2030. The role of environmental geochemistry in the aetiology of many cancers-as well as other non-communicable diseases-should not be understated, particularly in low- and middle-income countries where 70% of global cancer deaths occur and reliance on local geochemistry for drinking water and subsistence crops is still widespread. This article is an expansion of a series of presentations and discussions held at the 34th International Conference of the Society for Environmental Geochemistry and Health in Livingstone, Zambia, on the value of effective collaborations between environmental geochemists and cancer epidemiologists. Key technical aspects of each field are presented, in addition to a case study of the extraordinarily high incidence rates of oesophageal cancer in the East African Rift Valley, which may have a geochemical contribution. The potential merit of veterinary studies for investigating common geochemical risk factors between human and animal disease is also highlighted.


Sujet(s)
Exposition environnementale , Tumeurs de l'oesophage/étiologie , Tumeurs/épidémiologie , Tumeurs/étiologie , Afrique de l'Est/épidémiologie , Animaux , Cancérogènes/toxicité , Exposition environnementale/effets indésirables , Surveillance de l'environnement , Science environnementale , Tumeurs de l'oesophage/épidémiologie , Santé mondiale , Humains , Bétail
5.
Int J Cancer ; 147(2): 361-374, 2020 07 15.
Article de Anglais | MEDLINE | ID: mdl-31600408

RÉSUMÉ

Multimorbidity in women with breast cancer may delay presentation, affect treatment decisions and outcomes. We described the multimorbidity profile of women with breast cancer, its determinants, associations with stage at diagnosis and treatments received. We collected self-reported data on five chronic conditions (hypertension, diabetes, cerebrovascular diseases, asthma/chronic obstructive pulmonary disease, tuberculosis), determined obesity using body mass index (BMI) and tested HIV status, in women newly diagnosed with breast cancer between January 2016 and April 2018 in five public hospitals in South Africa. We identified determinants of ≥2 of the seven above-mentioned conditions (defined as multimorbidity), multimorbidity itself with stage at diagnosis (advanced [III-IV] vs. early [0-II]) and multimorbidity with treatment modalities received. Among 2,281 women, 1,001 (44%) presented with multimorbidity. Obesity (52.8%), hypertension (41.3%), HIV (22.0%) and diabetes (13.7%) were the chronic conditions that occurred most frequently. Multimorbidity was more common with older age (OR = 1.02; 95% CI 1.01-1.03) and higher household socioeconomic status (HSES) (OR = 1.06; 95% CI 1.00-1.13). Multimorbidity was not associated with advanced-stage breast cancer at diagnosis, but for self-reported hypertension there was less likelihood of being diagnosed with advanced-stage disease in the adjusted model (OR 0.80; 95% CI 0.64-0.98). Multimorbidity was associated with first treatment received in those with early-stage disease, p = 0.003. The prevalence of multimorbidity is high among patients with breast cancer. Our findings suggest that multimorbidity had a significant impact on treatment received in those with early-stage disease. There is need to understand the impact of multimorbidity on breast cancer outcomes.


Sujet(s)
Tumeurs du sein/épidémiologie , Diabète/épidémiologie , Infections à VIH/épidémiologie , Hypertension artérielle/épidémiologie , Obésité/épidémiologie , Adulte , Facteurs âges , Sujet âgé , Tumeurs du sein/anatomopathologie , Prise de décision clinique , Comorbidité , Femelle , Humains , Adulte d'âge moyen , Stadification tumorale , Prévalence , Appréciation des risques , Autorapport , Facteurs socioéconomiques , République d'Afrique du Sud/épidémiologie
6.
Sci Rep ; 9(1): 14447, 2019 10 08.
Article de Anglais | MEDLINE | ID: mdl-31595016

RÉSUMÉ

Soil, water and food supply composition data have been combined to primarily estimate micronutrient intakes and subsequent risk of deficiencies in each of the regions studied by generating new data to supplement and update existing food balance sheets. These data capture environmental influences, such as soil chemistry and the drinking water sources to provide spatially resolved crop and drinking water composition data, where combined information is currently limited, to better inform intervention strategies to target micronutrient deficiencies. Approximately 1500 crop samples were analysed, representing 86 food items across 50 sites in Tanzania in 2013 and >230 sites in Western Kenya between 2014 and 2018. Samples were analysed by ICP-MS for 58 elements, with this paper focussing on calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), selenium (Se), iodine (I), zinc (Zn) and molybdenum (Mo). In general, micronutrient supply from food groups was higher from Kilimanjaro,Tanzania than Counties in Western Kenya, albeit from a smaller sample. For both countries leafy vegetable and vegetable food groups consistently contained higher median micronutrient concentrations compared to other plant based food groups. Overall, calculated deficiency rates were <1% for Cu and Mo and close to or >90% for Ca, Zn and I in both countries. For Mg, a slightly lower risk of deficiency was calculated for Tanzania at 0 to 1% across simplified soil classifications and for female/males, compared to 3 to 20% for Kenya. A significant difference was observed for Se, where a 3 to 28% risk of deficiency was calculated for Tanzania compared to 93 to 100% in Kenya. Overall, 11 soil predictor variables, including pH and organic matter accounted for a small proportion of the variance in the elemental concentration of food. Tanzanian drinking water presented several opportunities for delivering greater than 10% of the estimated average requirement (EAR) for micronutrients. For example, 1 to 56% of the EAR for I and up to 10% for Se or 37% for Zn could be contributed via drinking water.


Sujet(s)
Régime alimentaire , Eau de boisson/composition chimique , Micronutriments/analyse , Sol/composition chimique , Produits agricoles/composition chimique , Analyse d'aliment , Humains , Kenya , Minéraux/analyse , Tanzanie
7.
Cancer Epidemiol Biomarkers Prev ; 28(12): 2005-2013, 2019 Dec.
Article de Anglais | MEDLINE | ID: mdl-31558508

RÉSUMÉ

BACKGROUND: Hot beverage consumption is a probable risk factor for esophageal squamous cell carcinoma (ESCC). No standardized exposure assessment protocol exists. METHODS: To compare how alternative metrics discriminate distinct drinking habits, we measured sip temperatures and sizes in an international group of hot beverage drinkers in France (n = 20) and hot porridge consumers (n = 52) in a high ESCC incidence region of China. Building on the knowledge that sip size and temperature affect intraesophageal liquid temperature (IELT), IELTs were predicted by modeling existing data, and compared with first sip temperature and, across all sips, mean temperature and sip-weighted mean temperature. RESULTS: Two contrasting exposure characteristics were observed. Compared with the international group, Chinese porridge consumers took larger first sips [mean difference +17 g; 95% confidence interval (CI), 13.3-20.7] of hotter (+9.5°C; 95% CI, 6.2-12.7) liquid, and their mean sip size did not vary greatly across sips, but the former groups increased in size as temperature decreased. This resulted in higher predicted IELTs (mean 61°C vs. 42.4°C) and sip-weighted temperatures (76.9°C vs. 56°C) in Chinese porridge consumers, and compared with first sip and mean temperature, these two metrics separated the groups to a greater extent. CONCLUSIONS: Distinguishing thermal exposure characteristics between these groups was greatly enhanced by measuring sip sizes. Temperature at first sip alone is suboptimal for assessing human exposure to hot foods and beverages, and future studies should include sip size measurements in exposure assessment protocols. IMPACT: This study provides a logistically feasible framework for assessing human exposure to hot beverages.


Sujet(s)
Boissons/effets indésirables , Comportement dipsique , Tumeurs de l'oesophage/étiologie , Carcinome épidermoïde de l'oesophage/étiologie , Température élevée/effets indésirables , Adulte , Sujet âgé , Chine/épidémiologie , Tumeurs de l'oesophage/épidémiologie , Carcinome épidermoïde de l'oesophage/épidémiologie , Femelle , Études de suivi , Humains , Incidence , Mâle , Adulte d'âge moyen , Pronostic , Jeune adulte
8.
J Expo Sci Environ Epidemiol ; 29(3): 335-343, 2019 04.
Article de Anglais | MEDLINE | ID: mdl-30242267

RÉSUMÉ

Element deficiencies and excesses play important roles in non-communicable disease aetiology. When investigating their roles in epidemiologic studies without prospective designs, reverse-causality limits the utility of transient biomarkers in cases. This study aimed to investigate whether surrogate participants may provide viable proxies by assessing concentration correlations within households. We obtained spot urine samples from 245 Tanzanian and Kenyan adults (including 101 household pairs) to investigate intra-household correlations of urinary elements (As, Ba, Ca, Cd, Co, Cs, Cu, Fe, Li, Mn, Mo, Ni, Pb, Rb, S, Se, Sr, Tl, V and Zn) and concentrations (also available for: Bi, Ce, Sb, Sn and U) relative to external population-levels and health-based values. Moderate-strong correlations were observed for As (r = 0.65), Cs (r = 0.67), Li (r = 0.56), Mo (r = 0.57), Se (r = 0.68) and Tl (r = 0.67). Remaining correlations were <0.41. Median Se concentrations in Tanzania (29 µg/L) and Kenya (24 µg/L) were low relative to 5738 Canadians (59 µg/L). Exceedances (of reference 95th percentiles) were observed for: Co, Mn, Mo, Ni and U. Compared to health-based values, exceedances were present for As, Co, Mo and Se but deficiencies were also present for Mo and Se. For well correlated elements, household members in East African settings provide feasible surrogate cases to investigate element deficiencies/excesses in relation to non-communicable diseases.


Sujet(s)
Caractéristiques familiales , Oligoéléments/urine , Adolescent , Adulte , Sujet âgé , Marqueurs biologiques/urine , Études cas-témoins , Femelle , Humains , Kenya , Mâle , Adulte d'âge moyen , Études prospectives , Tanzanie , Jeune adulte
9.
Int J Cancer ; 144(3): 459-469, 2019 02 01.
Article de Anglais | MEDLINE | ID: mdl-30117158

RÉSUMÉ

Squamous cell esophageal cancer is common throughout East Africa, but its etiology is poorly understood. We investigated the contribution of alcohol consumption to esophageal cancer in Kenya, based on a hospital-based case-control study conducted from 08/2013 to 03/2018 in Eldoret, western Kenya. Cases had an endoscopy-confirmed esophageal tumor whose histology did not rule out squamous cell carcinoma. Age and gender frequency-matched controls were recruited from hospital visitors/patients without digestive diseases. Logistic regression was used to calculate odds ratios (ORs) and their 95% confidence intervals (CI) adjusting for tobacco (type, intensity) and 6 other potential confounders. A total of 422 cases (65% male, mean at diagnosis 60 (SD 14) years) and 414 controls were included. ORs for ever-drinking were stronger in ever-tobacco users (9.0, 95% CI: 3.4, 23.8, with few tobacco users who were never drinkers) than in never-tobacco users (2.6, 95% CI: 1.6, 4.1). Risk increased linearly with number of drinks: OR for >6 compared to >0 to ≤2 drinks/day were 5.2 (2.4, 11.4) in ever-tobacco users and 2.1 (0.7, 4.4) in never-tobacco users. Although most ethanol came from low ethanol alcohols (busaa or beer), for the same ethanol intake, if a greater proportion came from the moonshine chang'aa, it was associated with a specific additional risk. The population attributable fraction for >2 drinks per day was 48% overall and highest in male tobacco users. Alcohol consumption, particularly of busaa and chang'aa, contributes to half of the esophageal cancer burden in western Kenya.


Sujet(s)
Consommation d'alcool/épidémiologie , Boissons alcooliques/classification , Tumeurs de l'oesophage/épidémiologie , Carcinome épidermoïde de l'oesophage/épidémiologie , Sujet âgé , Études cas-témoins , Femelle , Humains , Kenya/épidémiologie , Mâle , Adulte d'âge moyen , Risque
10.
Int J Cancer ; 145(1): 99-109, 2019 07 01.
Article de Anglais | MEDLINE | ID: mdl-30582155

RÉSUMÉ

There are no studies of oral health in relation to esophageal cancer in Africa, or of Eastern Africa's endemic dental fluorosis, an irreversible enamel hypo-mineralization due to early-life excessive fluoride intake. During 2014-18, we conducted a case-control study of squamous cell esophageal cancer in Eldoret, western Kenya. Odds ratios (AORs (95% confidence intervals)) were adjusted for design factors, tobacco, alcohol, ethnicity, education, oral hygiene and missing/decayed teeth. Esophageal cancer cases (N = 430) had poorer oral health and hygiene than controls (N = 440). Compared to no dental fluorosis, moderate/severe fluorosis, which affected 44% of cases, had a crude OR of 20.8 (11.6, 37.4) and on full adjustment was associated with 9.4-fold (4.6, 19.1) increased risk, whilst mild fluorosis (43% of cases) had an AOR of 2.3 (1.3, 4.0). The prevalence of oral leukoplakia and tooth loss/decay increased with fluorosis severity, and increased cancer risks associated with moderate/severe fluorosis were particularly strong in individuals with more tooth loss/decay. Using a mswaki stick (AOR = 1.7 (1.0, 2.9)) rather than a commercial tooth brush and infrequent tooth brushing also independently increased risk. Geographic variations showed that areas of high esophageal cancer incidence and those of high groundwater fluoride levels have remarkably similar locations across Eastern Africa. In conclusion, poor oral health in combination with, or as a result of, high-altitude susceptibility to hydro-geologically influenced dental fluorosis may underlie the striking co-location of Africa's esophageal cancer corridor with the Rift Valley. The findings call for heightened research into primary prevention opportunities of this highly fatal but common cancer.


Sujet(s)
Tumeurs de l'oesophage/épidémiologie , Carcinome épidermoïde de l'oesophage/épidémiologie , Fluorose dentaire/épidémiologie , Afrique/épidémiologie , Études cas-témoins , Femelle , Humains , Mâle , Adulte d'âge moyen , Santé buccodentaire/statistiques et données numériques , Prévalence
11.
Cancer Epidemiol ; 57: 45-52, 2018 12.
Article de Anglais | MEDLINE | ID: mdl-30300838

RÉSUMÉ

BACKGROUND: Case-control studies remain an important study design for aetiologic research on cancer, particularly when cohorts are not available. In addition to the potential biases inherent in this design, conducting fieldwork in settings with weak health care and information systems for cancer, such as in sub Saharan Africa, confer additional challenges which we present here with the aim to share experience to guide future studies. METHODS: We undertook a hospital-based case-control study of squamous cell esophageal cancer at the Moi Teaching and Referral Hospital in Eldoret, West Kenya. Cases were recruited at endoscopy and controls from hospital wards, age and gender frequency-matched to cases. Urine, toenails, blood and tumour biopsy were collected and a questionnaire administered. RESULTS: During this pilot phase, 143 cases and 155 controls were successfully recruited. Complete questionnaire data was obtained through e-data collection. Biospecimen collection was possible with support of an already existing equipped laboratory. We introduce changes made in the main study phase, including on expansion of the control groups to allow to consideration of selection bias. CONCLUSIONS: Extra attention and funding to train and monitor data quality and biospecimen collection and collaboration of a large group held together by strong leadership are essential. We recommend studies based on regional treatment centres with their more defined catchment areas rather than in the capital cities as referral routes in multi-level health care systems are severely attrition prone.


Sujet(s)
Études cas-témoins , Méthodes épidémiologiques , Tumeurs de l'oesophage/épidémiologie , Carcinome épidermoïde de l'oesophage/épidémiologie , Pays en voie de développement , Femelle , Humains , Kenya/épidémiologie , Mâle , Projets pilotes , Plan de recherche , Enquêtes et questionnaires
12.
Int J Cancer ; 143(11): 2732-2740, 2018 12 01.
Article de Anglais | MEDLINE | ID: mdl-29992553

RÉSUMÉ

There is a growing population of older women living with HIV/AIDS (WLWHA). Breast cancer is a common cancer in women worldwide, but the global number of breast cancers in WLWHA is not known. We estimated, for each UN sub-region, the number and age distribution of WLWHA who were diagnosed with breast cancer in 2012, by combining IARC-GLOBOCAN estimates of age-country specific breast cancer incidence with corresponding UNAIDS HIV prevalence. Primary analyses assumed no HIV-breast cancer association, and a breast cancer risk reduction scenario was also considered. Among 16.0 million WLWHA aged 15+ years, an estimated 6,325 WLWHA were diagnosed with breast cancer in 2012, 74% of whom were in sub-Saharan Africa, equally distributed between Eastern, Southern and Western Africa. In most areas, 70% of HIV-positive breast cancers were diagnosed under age 50. Among all breast cancers (regardless of HIV status), HIV-positive women constituted less than 1% of the clinical burden, except in Eastern, Western and Middle Africa where they comprised 4-6% of under age 50 year old breast cancer patients, and in Southern Africa where this patient subgroup constituted 26 and 8% of breast cancers diagnosed under and over age 50 respectively. If a deficit of breast cancer occurs in WLWHA, the global estimate would reduce to 3,600. In conclusion, worldwide, the number of HIV-positive women diagnosed with breast cancer was already substantial in 2012 and with an expected increase within the next decade, early detection and treatment research targeted to this population are needed.


Sujet(s)
Tumeurs du sein/épidémiologie , Infections à VIH/épidémiologie , Adolescent , Adulte , Afrique subsaharienne/épidémiologie , Répartition par âge , Sujet âgé , Tumeurs du sein/virologie , Femelle , VIH (Virus de l'Immunodéficience Humaine)/pathogénicité , Humains , Incidence , Prévalence , Jeune adulte
13.
Cancer Epidemiol ; 53: 119-128, 2018 04.
Article de Anglais | MEDLINE | ID: mdl-29414631

RÉSUMÉ

Esophageal squamous cell carcinoma (ESCC) remains the predominant histological subtype of esophageal cancer (EC) in many transitioning countries, with an enigmatic and geographically distinct etiology, and consistently elevated incidence rates in many Eastern and Southern African countries. To gain epidemiological insights into ESCC patterns across the continent, we conducted a systematic review and meta-analysis of male-to-female (M:F) sex ratios of EC age-standardised (world) incidence rates in Africa according to geography, time and age at diagnosis. Data from 197 populations in 36 countries were included in the analysis, based on data from cancer registries included in IARC's Cancer Incidence in Five Continents, Cancer in Africa and Cancer in Sub-Saharan Africa reports, alongside a systematic search of peer-reviewed literature. A consistent male excess in incidence rates overall (1.7; 95% CI: 1.4, 2.0), and in the high-risk Eastern (1.6; 95% CI: 1.4, 1.8) and Southern (1.8; 95% CI: 1.5, 2.0) African regions was observed. Within the latter two regions, there was a male excess evident in 30-39 year olds that was not observed in low-risk regions. Despite possible referral biases affecting the interpretability of the M:F ratios in place and time, the high degree of heterogeneity in ESCC incidence implies a large fraction of the disease is preventable, and directs research enquiries to elucidate early-age exposures among young men in Africa.


Sujet(s)
Tumeurs de l'oesophage/épidémiologie , Enregistrements/statistiques et données numériques , Adulte , Afrique/épidémiologie , Facteurs âges , Sujet âgé , Femelle , Géographie , Humains , Incidence , Mâle , Adulte d'âge moyen , Facteurs temps , Jeune adulte
14.
Ann Work Expo Health ; 61(7): 797-808, 2017 Aug 01.
Article de Anglais | MEDLINE | ID: mdl-28810689

RÉSUMÉ

OBJECTIVES: Mining and processing of chrysotile, an established carcinogen, has been undertaken in Asbest, Russian Federation since the late 1800s. Dust concentrations were routinely recorded at the open-pit mine and its asbestos-enrichment factories. We examined the temporal trends in these dust concentrations from 1951 to 2001. METHODS: Analyses included 89290 monthly averaged gravimetric dust concentrations in six factories (1951-2001) and 1457 monthly averaged concentrations in the mine (1964-2001). Annual percent changes (APC) in geometric mean dust concentrations were estimated for each factory and the mine separately from linear mixed models of the logarithmic-transformed monthly averaged concentrations. RESULTS: Dust concentrations declined significantly in the mine [APC: -1.6%; 95% confidence interval (CI): -3.0 to -0.2] and Factories 1-5 but not 6. Overall factory APCs ranged from -30.4% (95% CI: -51.9 to -8.9; Factory 1: 1951-1955) to -0.6% (95% CI: -1.5 to 0.2; Factory 6: 1969-2001). Factory trends varied across decades, with the steepest declines observed before 1960 [APCs: -21.5% (Factory 2) and -17.4% (Factory 3)], more moderate declines in the 1960s and 1970s [APCs from -10% in Factory 2 (1960s) to -0.3% (not statistically significant) in Factory 4 (1970s)], and little change thereafter. Mine dust concentrations increased in the 1960s (APC: +9.7%; 95% CI: 3.6 to 15.9), decreased in the 1990s (APC: -5.8%; 95% CI: -8.1 to -3.5) and were stable in between. CONCLUSIONS: In this analysis of >90000 dust concentrations, factory dust concentrations declined between 1951 and 1979 and then stabilized. In the mine, dust levels increased in the 1960s, declined in the 1990s and were unchanged in the interim.


Sujet(s)
Polluants atmosphériques d'origine professionnelle/analyse , Amiante/analyse , Poussière/analyse , Surveillance de l'environnement/méthodes , Mine , Amiante serpentine/analyse , Humains , Modèles linéaires , Russie
15.
Breast Cancer Res Treat ; 160(3): 531-537, 2016 12.
Article de Anglais | MEDLINE | ID: mdl-27757717

RÉSUMÉ

PURPOSE: Bimodal age distributions at diagnosis have been widely observed among US and European female breast cancer populations. To determine whether bimodal breast cancer distributions are also present in a sub-Saharan African population, we investigated female breast cancer in South Africa. METHODS: Using the South African National Cancer Registry data, we examined age-at-diagnosis frequency distributions (density plots) for breast cancer overall and by their receptor (oestrogen, progesterone and HER2) determinants among black and white women diagnosed during 2009-2011 in the public healthcare sector. For comparison, we also analysed corresponding 2010-2011 US SEER data. We investigated density plots using flexible mixture models, allowing early/late-onset membership to depend on receptor status. RESULTS: We included 8857 women from South Africa, 7176 (81 %) with known oestrogen receptor status, and 95064 US women. Bimodality was present in all races, with an early-onset mode between ages 40-50 years and a late-onset mode among ages 60-70 years. The early-onset mode was younger in South African black women (age 38), compared to other groups (45-54 years). CONCLUSIONS: Consistent patterns of bimodality and of its receptor determinants were present across breast cancer patient populations in South Africa and the US. Although the clinical spectrum of breast cancer is well acknowledged as heterogeneous, universal early- and late-onset age distributions at diagnosis suggest that breast cancer etiology consists of a mixture two main types.


Sujet(s)
, Tumeurs du sein/épidémiologie , , Adulte , Répartition par âge , Sujet âgé , Sujet âgé de 80 ans ou plus , Marqueurs biologiques tumoraux , Tumeurs du sein/diagnostic , Femelle , Humains , Adulte d'âge moyen , Surveillance de la population , Enregistrements , Programme SEER , République d'Afrique du Sud/épidémiologie , République d'Afrique du Sud/ethnologie , États-Unis/épidémiologie
16.
Cancer Epidemiol ; 40: 141-51, 2016 Feb.
Article de Anglais | MEDLINE | ID: mdl-26724463

RÉSUMÉ

Mammographic density (MD) is a quantitative trait, measurable in all women, and is among the strongest markers of breast cancer risk. The population-based epidemiology of MD has revealed genetic, lifestyle and societal/environmental determinants, but studies have largely been conducted in women with similar westernized lifestyles living in countries with high breast cancer incidence rates. To benefit from the heterogeneity in risk factors and their combinations worldwide, we created an International Consortium on Mammographic Density (ICMD) to pool individual-level epidemiological and MD data from general population studies worldwide. ICMD aims to characterize determinants of MD more precisely, and to evaluate whether they are consistent across populations worldwide. We included 11755 women, from 27 studies in 22 countries, on whom individual-level risk factor data were pooled and original mammographic images were re-read for ICMD to obtain standardized comparable MD data. In the present article, we present (i) the rationale for this consortium; (ii) characteristics of the studies and women included; and (iii) study methodology to obtain comparable MD data from original re-read films. We also highlight the risk factor heterogeneity captured by such an effort and, thus, the unique insight the pooled study promises to offer through wider exposure ranges, different confounding structures and enhanced power for sub-group analyses.


Sujet(s)
Tumeurs du sein/épidémiologie , Région mammaire/malformations , Glandes mammaires humaines/malformations , Mammographie/méthodes , Adulte , Sujet âgé , Densité mammaire , Tumeurs du sein/anatomopathologie , Femelle , Humains , Incidence , Agences internationales , Glandes mammaires humaines/anatomopathologie , Adulte d'âge moyen , Facteurs de risque
17.
Cancer Epidemiol Biomarkers Prev ; 24(12): 1898-901, 2015 Dec.
Article de Anglais | MEDLINE | ID: mdl-26404962

RÉSUMÉ

The association between leisure-time physical activity (LTPA) and male breast cancer risk is unclear. In the Male Breast Cancer Pooling Project, with 449 cases and 13,855 matched controls, we used logistic regression with study stratification to generate adjusted ORs and 95% confidence intervals (CI) for LTPA tertiles and male breast cancer risk. Compared with low LTPA, medium and high LTPA were not associated with male breast cancer risk (OR, 1.01; 95% CI, 0.79-1.29; 0.90, 0.69-1.18, respectively). In joint-effects analyses, compared with the referent of high body mass index (BMI; ≥25 kg/m(2))/low LTPA, neither medium nor high PA was associated with risk among high BMI men, but normal BMI men (<25 kg/m(2)) with low or medium LTPA were at a nonsignificant ∼16% reduced risk and those with high LTPA were at a 27% reduced risk (OR, 0.73; 95% CI, 0.50-1.07). Physical activity alone may not confer protection against male breast cancer risk.


Sujet(s)
Tumeur du sein de l'homme/épidémiologie , Activité motrice , Tumeur du sein de l'homme/étiologie , Études cas-témoins , Études de cohortes , Humains , Modèles logistiques , Mâle , Adulte d'âge moyen , Facteurs de risque
18.
Cancer Epidemiol Biomarkers Prev ; 24(3): 520-31, 2015 Mar.
Article de Anglais | MEDLINE | ID: mdl-25515550

RÉSUMÉ

BACKGROUND: The etiology of male breast cancer is poorly understood, partly due to its relative rarity. Although tobacco and alcohol exposures are known carcinogens, their association with male breast cancer risk remains ill-defined. METHODS: The Male Breast Cancer Pooling Project consortium provided 2,378 cases and 51,959 controls for analysis from 10 case-control and 10 cohort studies. Individual participant data were harmonized and pooled. Unconditional logistic regression was used to estimate study design-specific (case-control/cohort) ORs and 95% confidence intervals (CI), which were then combined using fixed-effects meta-analysis. RESULTS: Cigarette smoking status, smoking pack-years, duration, intensity, and age at initiation were not associated with male breast cancer risk. Relations with cigar and pipe smoking, tobacco chewing, and snuff use were also null. Recent alcohol consumption and average grams of alcohol consumed per day were also not associated with risk; only one subanalysis of very high recent alcohol consumption (>60 g/day) was tentatively associated with male breast cancer (ORunexposed referent = 1.29; 95% CI, 0.97-1.71; OR>0-<7 g/day referent = 1.36; 95% CI, 1.04-1.77). Specific alcoholic beverage types were not associated with male breast cancer. Relations were not altered when stratified by age or body mass index. CONCLUSIONS: In this analysis of the Male Breast Cancer Pooling Project, we found little evidence that tobacco and alcohol exposures were associated with risk of male breast cancer. IMPACT: Tobacco and alcohol do not appear to be carcinogenic for male breast cancer. Future studies should aim to assess these exposures in relation to subtypes of male breast cancer.


Sujet(s)
Consommation d'alcool/épidémiologie , Tumeur du sein de l'homme/épidémiologie , Fumer/épidémiologie , Consommation d'alcool/effets indésirables , Tumeur du sein de l'homme/étiologie , Études cas-témoins , Études de cohortes , Humains , Mâle , Facteurs de risque , Fumer/effets indésirables , Nicotiana/effets indésirables , États-Unis/épidémiologie
19.
Breast Cancer Res ; 15(5): R84, 2013.
Article de Anglais | MEDLINE | ID: mdl-24041225

RÉSUMÉ

INTRODUCTION: Estimates of the proportion of estrogen receptor negative (ERN) and triple-negative (TRN) breast cancer from sub-Saharan Africa are variable and include high values. Large studies of receptor status conducted on non-archival tissue are lacking from this region. METHODS: We identified 1218 consecutive women (91% black) diagnosed with invasive breast cancer from 2006­2012 at a public hospital in Soweto, South Africa. Immunohistochemistry based ER, progesterone receptor (PR) and human epidermal factor 2 (HER2) receptors were assessed at diagnosis on pre-treatment biopsy specimens. Mutually adjusted associations of receptor status with stage, age, and race were examined using risk ratios (RRs). ER status was compared with age-stratified US Surveillance Epidemiology and End Results program (SEER) data. RESULTS: 35% (95% confidence interval (CI): 32-38) of tumors were ERN, 47% (45-52) PRN, 26% (23-29) HER2P and 21% (18-23) TRN. Later stage tumors were more likely to be ERN and PRN (RRs 1.9 (1.1-2.9) and 2.0 (1.3-3.1) for stage III vs. I) but were not strongly associated with HER2 status. Age was not strongly associated with ER or PR status, but older women were less likely to have HER2P tumors (RR, 0.95 (0.92-0.99) per 5 years). During the study, stage III + IV tumors decreased from 66% to 46%. In black women the percentage of ERN (37% (34-40)) and PRN tumors (48% (45-52)) was higher than in non-black patients (22% (14-31) and 34% (25-44), respectively, P = 0.004 and P = 0.02), which remained after age and stage adjustment. Age-specific ERN proportions in black South African women were similar to those of US black women, especially for women diagnosed over age 50. CONCLUSION: Although a greater proportion of black than non-black South African women had ER-negative or TRN breast cancer, in all racial groups in this study breast cancer was predominantly ER-positive and was being diagnosed at earlier stages over time. These observations provide initial indications that late-stage aggressive breast cancers may not be an inherent feature of the breast cancer burden across Africa.


Sujet(s)
Tumeurs du sein/métabolisme , Tumeurs du sein/anatomopathologie , Récepteur ErbB-2/métabolisme , Récepteurs des oestrogènes/métabolisme , Récepteurs à la progestérone/métabolisme , Adulte , Facteurs âges , Sujet âgé , Sujet âgé de 80 ans ou plus , Tumeurs du sein/diagnostic , Tumeurs du sein/épidémiologie , Tumeur du sein de l'homme/diagnostic , Tumeur du sein de l'homme/épidémiologie , Tumeur du sein de l'homme/métabolisme , Tumeur du sein de l'homme/anatomopathologie , Femelle , Humains , Mâle , Adulte d'âge moyen , Grading des tumeurs , Stadification tumorale , Groupes de population , Programme SEER , République d'Afrique du Sud/épidémiologie , Facteurs temps , Tumeurs du sein triple-négatives/diagnostic , Tumeurs du sein triple-négatives/épidémiologie , Tumeurs du sein triple-négatives/métabolisme , Tumeurs du sein triple-négatives/anatomopathologie , Jeune adulte
20.
PLoS One ; 7(1): e29118, 2012.
Article de Anglais | MEDLINE | ID: mdl-22238588

RÉSUMÉ

BACKGROUND: Substantial increases in height have occurred concurrently with economic development in most populations during the last century. In high-income countries, environmental exposures that can limit genetic growth potential appear to have lessened, and variation in height by socioeconomic position may have diminished. The objective of this study is to investigate inequalities in height in a cohort of children born in the early 1990s in England, and to evaluate which factors might explain any identified inequalities. METHODS AND FINDINGS: 12,830 children from The Avon Longitudinal Study of Parents and Children (ALSPAC), a population based cohort from birth to about 11.5 years of age, were used in this analysis. Gender- and age-specific z-scores of height at different ages were used as outcome variables. Multilevel models were used to take into account the repeated measures of height and to analyze gender- and age-specific relative changes in height from birth to 11.5 years. Maternal education was the main exposure variable used to examine socioeconomic inequalities. The roles of parental and family characteristics in explaining any observed differences between maternal education and child height were investigated. Children whose mothers had the highest education compared to those with none or a basic level of education, were 0.39 cm longer at birth (95% CI: 0.30 to 0.48). These differences persisted and at 11.5 years the height difference was 1.4 cm (95% CI: 1.07 to 1.74). Several other factors were related to offspring height, but few changed the relationship with maternal education. The one exception was mid-parental height, which fully accounted for the maternal educational differences in offspring height. CONCLUSIONS: In a cohort of children born in the 1990s, mothers with higher education gave birth to taller boys and girls. Although height differences were small they persisted throughout childhood. Maternal and paternal height fully explained these differences.


Sujet(s)
Taille/physiologie , Relations parent-enfant , Parents , Classe sociale , Adulte , Poids et mesures du corps/statistiques et données numériques , Enfant , Enfant d'âge préscolaire , Études de cohortes , Angleterre/épidémiologie , Femelle , Humains , Nourrisson , Nouveau-né , Mâle , Facteurs socioéconomiques , Facteurs temps
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