https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(12)61766-8.pdf

A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010

In 1951 the British Medical Association forwarded to all British doctors a questionnaire about their smoking habits, and 34440 men replied. With few exceptions, all men who replied in 1951 have been followed for 20 years. The certified causes of all 10 072 deaths and subsequent changes in smoking habits were recorded. The ratio of the death rate among cigarette smokers to that among lifelong non-smokers of comparable age was, for men under 70 years, about 2:1, while for men over 70 years it was about 1-5:1. These ratios suggest that between a half and a third of all cigarette smokers will die because of their smoking, if the excess death rates are actually caused by smoking. To investigate whether this is the case, the relation of many different causes of death to age and tobacco consumption were examined, as were the effects of giving up smoking. Smoking caused death chiefly by heart disease among middle-aged men (and, with a less extreme relative risk, among old men,) lung cancer, chronic obstructive lung disease, and various vascular diseases. The distinctive features of this study were the completeness of follow-up, the accuracy of death certification, and the fact that the study population as a whole reduced its cigarette consumption substantially during the period of observation. As a result lung cancer grew relatively less common as the study progressed, but other cancers did not, thus illustrating in an unusual way the causal nature of the association between smoking and lung cancer.

https://www.bmj.com/content/bmj/328/7455/1519.full.pdf

Mortality in relation to smoking: 50 years' observations on male British doctors

Background. Infection with Helicobacter pylori has been linked with chronic atrophic gastritis, an inflammatory precursor of gastric adenocarcinoma. In a nested case–control study, we explored whether H. pylori infection increases the risk of gastric carcinoma. Methods. From a cohort of 128,992 persons followed since the mid-1960s at a health maintenance organization, 186 patients with gastric carcinoma were selected as case patients and were matched according to age, sex, and race with 186 control subjects without gastric carcinoma. Stored serum samples collected during the 1960s were tested for IgG antibodies to H. pylori by enzyme-linked immunosorbent assay. Data on cigarette use, blood group, ulcer disease, and gastric surgery were obtained from questionnaires administered at enrollment. Tissue sections and pathology reports were reviewed to confirm the histologic results. Results. The mean time between serum collection and the diagnosis of gastric carcinoma was 14.2 years. Of the 109 patient...

https://www.nejm.org/doi/pdf/10.1056/NEJM199110173251603

Helicobacter pylori infection and the risk of gastric carcinoma.

This volume is a single up-to-date source on the entire global epidemiology of diseases, injuries and risk factors with a comprehensive statement of methods and a complete presentation of results. It includes refined methods to assess data, ensure epidemiological consistency, and summarize the disease burden. Global Burden of Disease and Risk Factors examines the comparative importance of diseases, injuries, and risk factors; it incorporates a range of new data sources to develop consistent estimates of incidence, prevalence, severity and duration, and mortality for 136 major diseases and injuries. Drawing from more than 8,500 data sources that include epidemiological studies, disease registers, and notifications systems, this book incorporates information from more than 10,000 datasets relating to population health and mortality, representing one of the largest syntheses of global information on population health to date.

/pdf/global-burden-of-disease-and-risk-factors-2kzkym6sp5.pdf

Global burden of disease and risk factors

Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori.

Pathogenesis of Helicobacter pylori Infection

Objective: To assess the hazards at an early phase of the growing epidemic of deaths from tobacco in China. Design: Smoking habits before 1980 (obtained from family or other informants) of 0.7 million adults who had died of neoplastic, respiratory, or vascular causes were compared with those of a reference group of 0.2 million who had died of other causes. Setting: 24 urban and 74 rural areas of China. Subjects: One million people who had died during 1986-8 and whose families could be interviewed. Main outcome measures: Tobacco attributable mortality in middle or old age from neoplastic, respiratory, or vascular disease. Results: Among male smokers aged 35-69 there was a 51% (SE 2) excess of neoplastic deaths, a 31% (2) excess of respiratory deaths, and a 15% (2) excess of vascular deaths. All three excesses were significant (P 70 there was a 39% (3) excess of neoplastic deaths, a 54% (2) excess of respiratory deaths, and a 6% (2) excess of vascular deaths. Fewer women smoked, but those who did had tobacco attributable risks of lung cancer and respiratory disease about the same as men. For both sexes, the lung cancer rates at ages 35-69 were about three times as great in smokers as in non-smokers, but because the rates among non-smokers in different parts of China varied widely the absolute excesses of lung cancer in smokers also varied. Of all deaths attributed to tobacco, 45% were due to chronic obstructive pulmonary disease and 15% to lung cancer; oesophageal cancer, stomach cancer, liver cancer, tuberculosis, stroke, and ischaemic heart disease each caused 5-8%. Tobacco caused about 0.6 million Chinese deaths in 1990 (0.5 million men). This will rise to 0.8 million in 2000 (0.4 million at ages 35-69) or to more if the tobacco attributed fractions increase. Conclusions: At current age specific death rates in smokers and non-smokers one in four smokers would be killed by tobacco, but as the epidemic grows this proportion will roughly double. If current smoking uptake rates persist in China (where about two thirds of men but few women become smokers) tobacco will kill about 100 million of the 0.3 billion males now aged 0-29, with half these deaths in middle age and half in old age.

https://www.bmj.com/content/bmj/317/7170/1411.full.pdf

Emerging tobacco hazards in China: 1. Retrospective proportional mortality study of one million deaths.

To examine the geographic association between Helicobacter pylori infection and gastric cancer, we have assessed the prevalence of IgG antibodies to H. pylori in plasma samples taken in 1983 from 1882 men, aged 35-64 years, in 46 rural counties of the People's Republic of China. The gastric cancer mortality rates in these countries in 1973-75 varied from 3 per 1,000 (cumulative rate, 0-64 years) to 69 per 1,000, while the proportions of the population positive for H. pylori antibodies (based on an average of about 41 men per county) varied from 28% to 96%. After correction for the limited number of blood samples per county, the estimated correlation between H. pylori antibody prevalence and gastric cancer mortality was 40% (p = 0.02). No other type of cancer showed a significant association with H. pylori.

Geographic association of Helicobacter pylori antibody prevalence and gastric cancer mortality in rural China.

This report presents data from a number of recent surveys undertaken in China including the 1983 ecological survey the 1973-1975 mortality survey and the 1984 nitrosamine survey. "The chief purpose of the present monograph is simply to describe [population heterogeneity in China] by studying 65 rural counties and providing for each of them information on about 367 characteristics (82 standardized mortality rates from specific diseases and 285 biochemical and other characteristics chiefly from a special 1983 survey of adult blood urine diet and lifestyle in two randomly chosen villages in each of those 65 counties)." (EXCERPT)

Diet life-style and mortality in China: a study of the characteristics of 65 Chinese counties.

Overnight urine samples were collected from approximately 60 male adults in each of 69 counties of China in 1989. Two specimens were collected from each subject--one after a loading dose of proline and ascorbic acid and another after a loading dose of proline only. Levels of N-nitrosamino acids and nitrate were measured in urine samples and correlated with cumulative mortality rates for subjects aged between 0 and 64 years in the 1970s. Oesophageal cancer mortality rates were positively and significantly associated with (i) urinary levels of excreted N-nitrosoproline (NPRO) (after proline and ascorbic acid loading or proline loading only), (ii) N-nitrososarcosine levels, and (iii) nitrosation potential (the decrease in the amount of urinary NPRO after adding ascorbic acid to the proline load). There were also positive correlations between the urinary level of NPRO or other N-nitrosamino acids and that of nitrate. The urinary excretion of nitrate was associated with consumption of various nitrate-rich vegetables. The results suggest that N-nitroso compounds (NOC) or other nitrite-derived carcinogens are implicated in the aetiology of oesophageal cancer in China.

Geographic association between urinary excretion of N‐nitroso compounds and oesophageal cancer mortality in china

The relation between dietary vitamin C intake and pulmonary function was investigated in a cross-sectional study carried out in 69 counties in rural China in 1989. Within each of the 69 counties, 120 subjects aged 35-64 years were identified using a three-stage random clustering procedure. Each subject underwent pulmonary function testing, completed a detailed questionnaire, and provided a blood sample. Dietary vitamin C intakes were estimated among half of the subjects using a 3-day weighed record of household food intake. Plasma vitamin C was measured in sex-specific blood pools created from individual samples in each geographic area. Among the 3,085 subjects for whom there were complete data, dietary intake of vitamin C (151 mg/day (standard deviation, 111)) was significantly related to forced expiratory volume in the first second (FEV 1 ) and forced vital capacity after adjustment for sex, age, height, weight, total caloric intake, tobacco smoking, and education. An increase of 100 mg/day in vitamin C intake was associated with an increase of 21.6 ml (95% confidence interval -0.4 to 43.5) in FEV 1 and an increase of 24.9 ml (95% confidence interval 0.2 to 49.6) in forced vital capacity. No significant interaction with smoking status was observed. A significant positive association was also observed at the geographic level, between county-pooled plasma vitamin C and mean FEV 1 . These data support the hypothesis that dietary vitamin C may protect against the loss of pulmonary function.

T. C. Campbell

Papers

Emerging tobacco hazards in China: 1. Retrospective proportional mortality study of one million deaths.

Geographic association of Helicobacter pylori antibody prevalence and gastric cancer mortality in rural China.

Diet life-style and mortality in China: a study of the characteristics of 65 Chinese counties.

Geographic association between urinary excretion of N‐nitroso compounds and oesophageal cancer mortality in china

Dietary vitamin C intake and lung function in rural China