There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

background The influence of excess body weight on the risk of death from cancer has not been fully characterized. methods In a prospectively studied population of more than 900,000 U.S. adults (404,576 men and 495,477 women) who were free of cancer at enrollment in 1982, there were 57,145 deaths from cancer during 16 years of follow-up. We examined the relation in men and women between the body-mass index in 1982 and the risk of death from all cancers and from cancers at individual sites, while controlling for other risk factors in multivariate proportional-hazards models. We calculated the proportion of all deaths from cancer that was attributable to overweight and obesity in the U.S. population on the basis of risk estimates from the current study and national estimates of the prevalence of overweight and obesity in the U.S. adult population. results The heaviest members of this cohort (those with a body-mass index [the weight in kilograms divided by the square of the height in meters] of at least 40) had death rates from all cancers combined that were 52 percent higher (for men) and 62 percent higher (for women) than the rates in men and women of normal weight. For men, the relative risk of death was 1.52 (95 percent confidence interval, 1.13 to 2.05); for women, the relative risk was 1.62 (95 percent confidence interval, 1.40 to 1.87). In both men and women, body-mass index was also significantly associated with higher rates of death due to cancer of the esophagus, colon and rectum, liver, gallbladder, pancreas, and kidney; the same was true for death due to non-Hodgkin’s lymphoma and multiple myeloma. Significant trends of increasing risk with higher body-mass-index values were observed for death from cancers of the stomach and prostate in men and for death from cancers of the breast, uterus, cervix, and ovary in women. On the basis of associations observed in this study, we estimate that current patterns of overweight and obesity in the United States could account for 14 percent of all deaths from cancer in men and 20 percent of those in women. conclusions Increased body weight was associated with increased death rates for all cancers combined and for cancers at multiple specific sites.

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Overweight, obesity, and mortality from cancer in a prospectively studied cohort of U.S. adults.

The main threats to human health from heavy metals are associated with exposure to lead, cadmium, mercury and arsenic. These metals have been extensively studied and their effects on human health regularly reviewed by international bodies such as the WHO. Heavy metals have been used by humans for thousands of years. Although several adverse health effects of heavy metals have been known for a long time, exposure to heavy metals continues, and is even increasing in some parts of the world, in particular in less developed countries, though emissions have declined in most developed countries over the last 100 years. Cadmium compounds are currently mainly used in re-chargeable nickel-cadmium batteries. Cadmium emissions have increased dramatically during the 20th century, one reason being that cadmium-containing products are rarely re-cycled, but often dumped together with household waste. Cigarette smoking is a major source of cadmium exposure. In non-smokers, food is the most important source of cadmium exposure. Recent data indicate that adverse health effects of cadmium exposure may occur at lower exposure levels than previously anticipated, primarily in the form of kidney damage but possibly also bone effects and fractures. Many individuals in Europe already exceed these exposure levels and the margin is very narrow for large groups. Therefore, measures should be taken to reduce cadmium exposure in the general population in order to minimize the risk of adverse health effects. The general population is primarily exposed to mercury via food, fish being a major source of methyl mercury exposure, and dental amalgam. The general population does not face a significant health risk from methyl mercury, although certain groups with high fish consumption may attain blood levels associated with a low risk of neurological damage to adults. Since there is a risk to the fetus in particular, pregnant women should avoid a high intake of certain fish, such as shark, swordfish and tuna; fish (such as pike, walleye and bass) taken from polluted fresh waters should especially be avoided. There has been a debate on the safety of dental amalgams and claims have been made that mercury from amalgam may cause a variety of diseases. However, there are no studies so far that have been able to show any associations between amalgam fillings and ill health. The general population is exposed to lead from air and food in roughly equal proportions. During the last century, lead emissions to ambient air have caused considerable pollution, mainly due to lead emissions from petrol. Children are particularly susceptible to lead exposure due to high gastrointestinal uptake and the permeable blood-brain barrier. Blood levels in children should be reduced below the levels so far considered acceptable, recent data indicating that there may be neurotoxic effects of lead at lower levels of exposure than previously anticipated. Although lead in petrol has dramatically decreased over the last decades, thereby reducing environmental exposure, phasing out any remaining uses of lead additives in motor fuels should be encouraged. The use of lead-based paints should be abandoned, and lead should not be used in food containers. In particular, the public should be aware of glazed food containers, which may leach lead into food. Exposure to arsenic is mainly via intake of food and drinking water, food being the most important source in most populations. Long-term exposure to arsenic in drinking-water is mainly related to increased risks of skin cancer, but also some other cancers, as well as other skin lesions such as hyperkeratosis and pigmentation changes. Occupational exposure to arsenic, primarily by inhalation, is causally associated with lung cancer. Clear exposure-response relationships and high risks have been observed.

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Hazards of heavy metal contamination.

https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(08)60269-X.pdf

Body-mass index and incidence of cancer: a systematic review and meta-analysis of prospective observational studies

The prevalence of obesity is rapidly increasing globally. Epidemiological studies have associated obesity with a range of cancer types, although the mechanisms by which obesity induces or promotes tumorigenesis vary by cancer site. These include insulin resistance and resultant chronic hyperinsulinaemia, increased bioavailability of steroid hormones and localized inflammation. Gaining a better understanding of the relationship between obesity and cancer can provide new insight into mechanisms of cancer pathogenesis.

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Overweight, obesity and cancer: epidemiological evidence and proposed mechanisms

Few large-scale epidemiologic studies have quantified the possible link between obesity and chronic renal failure (CRF) This study analyzed anthropometric data from a nationwide, population-based, case-control study of incident, moderately severe CRF Eligible as cases were all native Swedes who were aged 18 to 74 yr and had CRF and whose serum creatinine for the first time and permanently exceeded 34 mg/dl (men) or 28 mg/dl (women) during the study period A total of 926 case patients and 998 control subjects, randomly drawn from the study base, were enrolled Face-to-face interviews, supplemented with self-administered questionnaires, provided information about anthropometric measures and other lifestyle factors Logistic regression models with adjustments for several co-factors estimated the relative risk for CRF in relation to body mass index (BMI) Overweight (BMI>or=25 kg/m2) at age 20 was associated with a significant three-fold excess risk for CRF, relative to BMI or=30) among men and morbid obesity (BMI>or=35) among women anytime during lifetime was linked to three- to four-fold increases in risk The strongest association was with diabetic nephropathy, but two- to three-fold risk elevations were observed for all major subtypes of CRF Analyses that were confined to strata without hypertension or diabetes revealed a three-fold increased risk among patients who were overweight at age 20, whereas the two-fold observed risk elevation among those who had a highest lifetime BMI of >35 was statistically nonsignificant Obesity seems to be an important-and potentially preventable-risk factor for CRF Although hypertension and type 2 diabetes are important mediators, additional pathways also may exist

Obesity and Risk for Chronic Renal Failure

Obesity has been associated with an increased risk of renal cell cancer among women, while the evidence for men is considered weaker. We conducted a quantitative summary analysis to evaluate the existing evidence that obesity increases the risk of renal cell cancer both among men and women. We identified all studies examining body weight in relation to kidney cancer, available in MEDLINE from 1966 to 1998. The quantitative summary analysis was limited to studies assessing obesity as body mass index (BMI, kg m−2), or equivalent. The risk estimates and the confidence intervals were extracted from the individual studies, and a mixed effect weighted regression model was used. We identified 22 unique studies on each sex, and the quantitative analysis included 14 studies on men and women, respectively. The summary relative risk estimate was 1.07 (95% CI 1.05–1.09) per unit of increase in BMI (corresponding to 3 kg body weight increase for a subject of average height). We found no evidence of effect modification by sex. Our quantitative summary shows that increased BMI is equally strongly associated with an increased risk of renal cell cancer among men and women. © 2001 Cancer Research Campaignhttp://www.bjcancer.com

/pdf/obesity-and-renal-cell-cancer-a-quantitative-review-vq7goixsrg.pdf

Obesity and renal cell cancer--a quantitative review.

Background Several epidemiologic studies have demonstrated an association between heavy consumption of nonnarcotic analgesics and the occurrence of chronic renal failure, but it is unclear which is the cause and which is the effect. Methods In a nationwide, population-based, case–control study of early-stage chronic renal failure in Sweden, face-to-face interviews were conducted with 926 patients with newly diagnosed renal failure and 998 control subjects, of whom 918 and 980, respectively, had complete data. We used logistic-regression models to estimate the relative risks of disease-specific types of chronic renal failure associated with the use of various analgesics. Results Aspirin and acetaminophen were used regularly by 37 percent and 25 percent, respectively, of the patients with renal failure and by 19 percent and 12 percent, respectively, of the controls. Regular use of either drug in the absence of the other was associated with an increase by a factor of 2.5 in the risk of chronic renal failure ...

Acetaminophen, Aspirin, and Chronic Renal Failure

To investigate the relation between diabetes mellitus and the risk of renal cell cancer we carried out a population-based retrospective cohort study. Patients identified in the Swedish Inpatient Register who were discharged from hospitals with a diagnosis of diabetes mellitus between 1965 and 1983 formed a cohort of 153 852 patients (80 005 women and 73 847 men). The cohort members were followed up to 1989 by record linkage to three nation-wide registries. Standardized incidence ratios (SIRs) and standardized mortality ratios (SMRs) were computed using age-specific sex-specific and period-specific incidence and mortality rates derived from the entire Swedish population. After exclusion of the first year of observation, a total of 267 incidences of renal cell cancer (ICD-7 : 180.0) occurred in diabetic patients compared with the 182.4 that had been expected. Increased risks were observed in both women (SIR = 1.7, 95 % confidence interval, CI = 1.4–2.0) and men (SIR = 1.3; 95 % CI = 1.1–1.6) throughout the duration of follow-up (1–25 years). A higher risk was seen for kidney cancer (ICD-7 : 180) mortality (SMR = 1.9; 95 % CI = 1.7–2.2, women; SMR 1.7, 95 % CI = 1.4–1.9, men). In comparison with the general population, patients with diabetes mellitus have an increased risk of renal cell cancer. [Diabetologia (1999) 42: 107–112]

https://link.springer.com/content/pdf/10.1007%2Fs001250051122.pdf

The role of diabetes mellitus in the aetiology of renal cell cancer

The relationship between renal-cell cancer (RCC) and occupation was investigated in an international multicenter population-based case-control study. Study centers in Australia, Denmark, Germany, S ...

Per Lindblad

Papers

Obesity and Risk for Chronic Renal Failure

Obesity and renal cell cancer--a quantitative review.

Acetaminophen, Aspirin, and Chronic Renal Failure

The role of diabetes mellitus in the aetiology of renal cell cancer

International renal-cell cancer study. IV. Occupation