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  • Human immunodeficiency virus infection and cancer

    16 October 2018

    Infectious agents are a significant and theoretically preventable cause of cancer. Therefore, the identification of additional cancers with an infectious aetiology has important public health implications. There is evidence that immunosuppression leads to the selective development of certain cancers that are known or thought to be caused by infections. The fact that millions of people are now infected with HIV has provided an unprecedented opportunity to investigate the role of the immune system in the aetiology of cancer, as well as possibly identifying new cancers with an infectious cause. There is good evidence that immunosuppression associated with HIV infection increases the risk of Kaposi's sarcoma, non-Hodgkin's lymphoma, squamous cell carcinoma of the conjunctiva, Hodgkin's disease and leiomyosarcoma in children. Most of these cancers are thought to be caused by specific human herpesviruses. Few other cancers show a large increase in risk associated with HIV infection, although relatively small increases for rare tumours cannot be excluded. The available evidence suggests that invasive cervix cancer and hepatocellular cancer, both of which are known to be caused by infectious agents, do not appear to be increased markedly in people with HIV or AIDS. There is mounting evidence that causal factors in the aetiology of HIV associated cancers are similar to those for the same cancers occurring in the general population. Similarly, the personal characteristics of those who develop a specific cancer are similar among HIV infected and HIV uninfected individuals with the same tumour. The main determinant of Kaposi's risk is known to be infection with HHV8, and this infection is identified in both HIV seropositive and HIV seronegative adults and children (Boshoff, this volume). Case-control studies from Uganda show that the personal characteristics of those who develop Kaposi's sarcoma show striking similarities between those with and without HIV infection and that these individuals are distinguished by features of wealth and high social status (Ziegler et al, 1997, 1998). Viral genomes and viral gene products of the Epstein-Barr virus have been found in tumour tissue of subjects with non-Hodgkin's lymphoma, but they tend to be found more often in immunosuppressed people than in the immunocompetent. The implications of this are unclear, but there is evidence that the viral load of both HHV8 ad EBV increases with increasing levels of immune impairment (Boshoff, this volume, Rickinson et al, 1997), which in turn would make the virus easier to detect with current technology. This has important implications for research on HIV associated cancers. It would seem probable that the same factors that are important in the aetiology of cancer in those with HIV infection are also important in the aetiology of cancer in those without HIV infection. Furthermore, an infectious cause is likely to be easier to identify in the immunosuppressed than in the immunocompetent. Therefore, the study of HIV associated cancers is likely to be of relevance to the population as a whole. There may be other cancers whose incidence is increased in association with HIV infection, but, if so, they are probably rare, and the associated relative risks are not likely to be large. Further research is needed to clarify which other tumours are increased in people with HIV and the magnitude of the associated relative risk in those that are. In particular, there is a need for further record linkage studies in populations where HIV prevalence is low and for further case-control studies in populations where HIV prevalence is high. In the mean time, because the number of specific cancers reported in any single study tends to be small, it would be valuable to combine the results from existing studies. Understanding why immunosuppression increases the risk of certain, but not all, cancers that are known to be caused by infectious agents may lead to important insights into the carcinogenic process. In addition, understanding why certain viruses can be found in association with tumours in HIV seropositive subjects, but not in similar tumours in HIV seronegative subjects, may aid our understanding of the role of these infections in the aetiology of cancer in the general population. With the prospect of improved survival for HIV infected people and the wider relevance of such research it will become increasingly important to known more about the risk of cancer in these individuals.

  • Leukaemia mortality in three UK nuclear industry workforces: Comparison with the BEIR v model

    16 October 2018

    Our previous comparison of risk of death from leukaemia associated with external radiation dose in over 75000 UK nuclear industry workers with that for adult Japanese atomic bomb survivors reported by UNSCEAR in 1988, suggested that the estimated excess relative risk per Sv in the two populations was similar (ratio of risks=1.1, 90% confidence interval +0.2 to +3.1). The further analysis described here, which compares leukaemia risk in the workers with that predicted by the linear term of the BEIR V model for leukaemia, resulted in a ratio of 1. 3(90% confidence interval -0.2 to +4.5). Leukaemia risk in this population of nuclear industry workers is therefore consistent with that predicted by the BEIR V model. That our data are also compatible with risks from zero to around five times those predicted by this model demonstrates that even a very substantial occupational cohort such as ours can provide only a limited amount of information about the magnitude of leukaemia risks in adults exposed to low doses of external radiation relative to those exposed to high doses and high dose rates.

  • Administration of stable iodine to the population around the Chernobyl nuclear power plant

    16 October 2018

    A very large amount (2.5 × 1017Bq) of radioactive iodine was released as a result of the Chernobyl accident in 1986. An effective protective action that may be employed to reduce the potential radiation dose to the thyroid gland after a serious nuclear reactor accident is the administration of stable iodide in the form of potassium iodide (KI). Potassium iodide was reportedly given to nearly five and a half million persons after the Chernobyl accident. During the International Chernobyl Project, medical investigators asked the general population in both highly contaminated and control settlements about thyroid prophylaxis. Only 25% of persons currently living in the most contaminated regions reported taking potassium iodide. Sixty-six percent indicated that they did not take potassium iodide and 9% were uncertain. Of those who took stable iodine prophylactically, 44% indicated that it was in solution, 44% that it was in tablets and 12% did not remember how it was administered. Only about one third of persons were able to indicate the duration of time that they took such medication. The average was 6.2 days. It appears that iodine prophylaxis will not have a major impact on estimated collective thyroid doses to the general population living around the Chernobyl nuclear power plant. The impact that distribution of KI had upon plant and emergency accident workers remains unknown to us.

  • The epidemiology of ovarian cancer

    16 October 2018

    This paper reviews evidence on the distribution of ovarian cancer in the community and on the characteristics of women who develop ovarian cancer. In general these data highlight the importance of the repeated stimulation of the ovary by "incessant ovulation" in the aetiology of the malignancy - factors such as pregnancy and oral contraceptive use which suppress ovulation protect against ovarian cancer. The increasing incidence of ovarian cancer in many Western countries has probably resulted from the decreasing average number of children born to successive generations of women. © 1980.

  • Development and evaluation of the oxford WebQ, a low-cost, web-based method for assessment of previous 24 h dietary intakes in large-scale prospective studies

    16 October 2018

    Objectives To describe the development of the Oxford WebQ, a web-based 24 h dietary assessment tool developed for repeated administration in large prospective studies; and to report the preliminary assessment of its performance for estimating nutrient intakes. Design We developed the Oxford WebQ by repeated testing until it was sufficiently comprehensive and easy to use. For the latest version, we compared nutrient intakes from volunteers who completed both the Oxford WebQ and an interviewer-administered 24 h dietary recall on the same day. Setting Oxford, UK. Subjects A total of 116 men and women. Results The WebQ took a median of 12.5 (interquartile range: 10.8-16.3) min to self-complete and nutrient intakes were estimated automatically. By contrast, the interviewer-administered 24 h dietary recall took 30 min to complete and 30 min to code. Compared with the 24 h dietary recall, the mean Spearman's correlation for the 21 nutrients obtained from the WebQ was 0.6, with the majority between 0.5 and 0.9. The mean differences in intake were less than .10 % for all nutrients except for carotene and vitamins B12 and D. On rare occasions a food item was reported in only one assessment method, but this was not more frequent or systematically different between the methods. Conclusions Compared with an interviewer-based 24 h dietary recall, the WebQ captures similar food items and estimates similar nutrient intakes for a single day's dietary intake. The WebQ is self-administered and nutrients are estimated automatically, providing a low-cost method for measuring dietary intake in large-scale studies. © 2011 The Authors.

  • The spectrum of HIV-1 related cancers in South Africa.

    16 October 2018

    Despite the high prevalence of infection by the Human Immunodeficiency Virus (HIV) in South Africa, information on its association with cancer is sparse. Our study was carried out to examine the relationship between HIV and a number of cancer types or sites that are common in South Africa. A total of 4,883 subjects, presenting with a cancer or cardiovascular disease at the 3 tertiary referral hospitals in Johannesburg, were interviewed and had blood tested for HIV. Odds ratios associated with HIV infection were calculated by using unconditional logistic regression models for 16 major cancer types where data was available for 50 or more patients. In the comparison group, the prevalence of HIV infection was 8.3% in males and 9.1% in females. Significant excess risks associated with HIV infection were found for Kaposi's sarcoma (OR=21.9, 95% CI=12.5-38.6), non-Hodgkin lymphoma (OR=5.0, 95%CI=2.7-9.5), vulval cancer (OR=4.8, 95%CI= 1.9-12.2) and cervical cancer (OR= 1.6, 95%CI= 1.1-2.3) but not for any of the other major cancer types examined, including Hodgkin disease, multiple myeloma and lung cancer. In Johannesburg, South Africa, HIV infection was associated with significantly increased risks of Kaposi's sarcoma, non-Hodgkin lymphoma and cancers of the cervix and the vulva. The relative risks for Kaposi's sarcoma and non-Hodgkin lymphoma associated with HIV infection were substantially lower than those found in the West.

  • Hormone replacement therapy and incidence of central nervous system tumours in the Million Women Study.

    16 October 2018

    We examined the relation between the use of hormone replacement therapy (HRT) and the incidence of central nervous system (CNS) tumours in a large prospective study of 1,147,894 postmenopausal women. Women were aged 56.6 years on average at entry, and HRT use was recorded at recruitment and updated, where possible, about 3 years later. During a mean follow-up of 5.3 years per woman, 1,266 CNS tumours were diagnosed, including 557 gliomas, 311 meningiomas and 117 acoustic neuromas. Compared with never users of HRT, the relative risks (RRs) for all incident CNS tumours, gliomas, meningiomas and acoustic neuromas in current users of HRT were 1.20 (95% CI: 1.05-1.36), 1.09 (95% CI: 0.89-1.32), 1.34 (95% CI: 1.03-1.75) and 1.58 (95% CI: 1.02-2.45), respectively, and there was no significant difference in the relative risks by tumour type (heterogeneity p = 0.2). In past users of HRT the relative risk was 1.07 (95% CI: 0.93-1.24) for all CNS tumours. Among current users of HRT, there was significant heterogeneity by the type of HRT with the users of oestrogen-only HRT at higher risk of all CNS tumours than users of oestrogen-progestagen HRT (RR = 1.42, 95% CI: 1.21-1.67 versus RR = 0.97, 95% CI: 0.82-1.16) (heterogeneity p < 0.001). Among current users of oestrogen-only and oestrogen-progestagen HRT, there was no significant heterogeneity by duration of use, hormonal constituent or mode of administration of HRT.

  • Cholesterol

    21 June 2016

    Blood lipids are a major cause of cardiovascular disease (CVD). Higher levels of LDL cholesterol and lower levels of HDL cholesterol are associated with higher heart disease risk. While this has been known for some time, it is only in recent decades that effective treatments to substantially lower LDL cholesterol have become available.

  • Smoking

    21 June 2016

    The link between smoking and lung cancer was originally discovered by Sir Richard Doll in 1956. Co-director Sir Richard Peto has continued to study the impact of tobacco of global health (see video below). Smoking cigarettes is a leading cause of premature death worldwide. There were about 100 million deaths from tobacco in the 20th century, most in developed countries. If current smoking patterns persist, it is estimated that tobacco will kill about 1 billion people this century, mostly in low- and middle-income countries, and about half of these deaths will occur before age 70.

  • Diabetes Mellitus

    21 June 2016

    Diabetes Mellitus is a group of metabolic disorders in which there are high blood sugars over a prolonged period. Rates of type-2 (or adult onset) diabetes have increased rapidly in recent decades due to changes in diet and other lifestyle factors. Patients with diabetes are at increased risk of a number of diseases, most notably cardiovascular disease, kidney disease and damage to the eyes.

  • Other Chronic Diseases

    21 June 2016

    Chronic disease is responsible for a major part of our society’s burden of disability. In addition to our research into chronic diseases such as cancer, cardiovascular disease, diabetes and renal disease we conduct a range of research into other diseases, as well as into the care of people with chronic conditions.