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9.1 - 9.9 See text.
9.10 Calorie restriction during childhood and prostate cancer risk later in life. A study investigated the incidence of prostate cancer in 58,279 men between the ages of 55 and 69. Men were classified according to whether they had experienced caloric restrictions during childhood. Rates of prostate cancer were compared in those exposed to caloric restriction and those that were not exposed to such deprivation (Am J Epidemiol, 2001;154:530-537).
9.11 Tea consumption in relation to CHD. The relation of tea to cholesterol,
systolic blood pressure, and mortality from coronary heart disease and all
causes was studied in 9,856 men and 10,233 women without history of
cardiovascular disease or diabetes. All men and women 35-49 years of age from
the county of Oppland (Norway) were invited to participate; the attendance rate
was 90%. RESULTS. Mean serum cholesterol decreased with increasing tea
consumption, the linear trend coefficient corresponded to a difference of 0.24
mmol/liter (9.3 mg/dl) in men and 0.15 mmol/liter (5.8 mg/dl) in women between
drinkers of less than one cup and those of five or more cups/day, when other
risk factors were taken into account. Systolic blood pressure was inversely
related to tea with a difference between the same two tea groups of 2.1 mm in
men and 3.5 mm in women. Altogether 396 men and 237 women died from all causes,
and of these 141 and 18, respectively, died from coronary heart disease during
the 12-year follow-up period. The mortality rate was higher (not statistically
significant) among persons drinking no tea or less than one cup compared with
persons drinking one or more cups/day. This applies to men and women and to
coronary heart disease and all-cause mortality. For men, the relative risk (one
or more versus less than one cup) for coronary death from Cox regression was
0.64 (95% CI: 0.38, 1.07).(Stensvold
et al., Prev Med, 1992,21:546-53.).
9.12 Effectiveness of antibiotics in preventing post-op infections. Surgical patients were randomly assigned to one of three
groups. Group 1 received antibiotics 24 hours prior to surgery, group 2 received
antibiotics 2 hours prior to surgery, and group 3 received no antibiotics prior
to surgery.
Post-operative infection rates were determined and compared.
9.13 British folic acid study 1. Researchers in Liverpool, England published a landmark study in which 66% of the mothers who had given birth to infants with spinal cord malformations were folic acid deficient. In contrast, mothers who had normal babies were shown to be folic acid deficient 17% of the time (Lancet 1965; i, 1254 - 1256).
9.14 British folic acid study 2. The British Research Council completed a study in which some of the women in a group who had given birth to babies with neural tube defects in the past and who were once again pregnant were supplemented with folic acid during pregnancy. The investigators found that supplementation reduced the risk of having second neural tube defect baby by 70% (Lancet 1991;338:131-137; PubMed).
9.15 Optimists and pessimists. At the Mayo Clinic in Rochester, Minnesota, researchers studied 939 patients who had been classified as either optimists or pessimists. After thirty years, a greater percentage of optimists were alive than pessimists (Mayo Clinic Proceedings 2000;75:140-143).
9.16 Community survey. A random sample of individuals from a community revealed a higher prevalence of diabetes in Hispanics than in non-Hispanics.
9.17 Trends in post-neonatal mortality. Using vital statistics from local health departments, researchers found post-neonatal mortality rates in Greenland had declined during the last 25 years. In contrast, little progress has been made in decreasing neonatal mortality.
9.18 Community-Level Predictors of Pneumococcal Carriage and Resistance in Young Children. Pneumococcal carriage and resistance vary markedly among communities and are not fully explained by individual predictors. Community risk factors may explain this variation. The authors of this study geocoded addresses from a multicommunity sample of 710 Massachusetts children previously swabbed for pneumococcal carriage. Using regression models, the authors evaluated associations between census tract measures and pneumococcal carriage or resistance. Living in census tracts with an average household size of more than 2.9 predicted carriage (odds ratio = 3.0, 95% confidence interval: 1.7, 5.5), and living in socioeconomically disadvantaged census tracts conferred an additional two- to threefold odds of carriage equal to attending child care. Living in a census tract with a median household income of less than $35,000 predicted carriage among nonattendees (odds ratio = 2.7, 95% confidence interval: 1.7, 4.3). The predictive value of a low-income census tract was interchangeable with any of several socioeconomic measures, including poverty, unemployment, low educational attainment, and low owner occupancy, in addition to high density of children and limited household plumbing facilities. Furthermore, living in census tracts with low educational attainment significantly predicted resistance (odds ratio = 4.0, 95% confidence interval: 1.3, 12.7) and was interchangeable with a high density of children (odds ratio = 3.5, 95% confidence interval: 1.0, 11.7). The two- to threefold odds of pneumococcal carriage conferred by certain community characteristics suggest that these measures may target communities for interventions to decrease transmission. (American Journal of Epidemiology; 2004; 159:645 - 654).
9.19 Pancreatic Cancer and Drinking Water and Dietary Sources of Nitrate and Nitrite. N-Nitroso compounds, known animal carcinogens, are formed endogenously from drinking water and dietary sources of nitrate and nitrite. The authors conducted a a study of pancreatic cancer in Iowa to determine whether increased consumption of nitrate and nitrite from drinking water and dietary sources was associated with risk. They linked detailed water source histories to nitrate measurements for Iowa community water supplies. After exclusions for insufficient data, 1,244 controls and 189 pancreatic cancer cases were available for analysis. Among controls, the median average nitrate level (1960–1987) was 1.27 (interquartile range, 0.6–2.8) mg of nitrate nitrogen per liter of water. No association was observed between pancreatic cancer risk and increasing quartiles of the community water supplies’ nitrate level. Increasing intake of dietary nitrite from animal sources was associated with an elevated risk of pancreatic cancer among men and women (highest quartile odds ratios = 2.3, 95% confidence interval: 1.1, 5.1, for men and 3.2, 95% confidence interval: 1.6, 6.4, for women). In contrast, dietary nitrate intake showed an inverse association with risk among women and no association among men. This study suggests that long-term exposure to drinking water nitrate at levels below the maximum contaminant level of nitrate nitrogen (10 mg/liter) is not associated with pancreatic cancer; however, the consumption of dietary nitrite from animal products may increase risk (American Journal of Epidemiology, 2004; 159:693 - 701 -- full text).