Diet, obesity and low physical activity

Avoidable cancer cases in the Nordic countries - The impact of overweight and obesity

BACKGROUND

Several types of cancers are causally linked to overweight and obesity, which are increasing in the Nordic countries. The aim of this study was to quantify the proportion of the cancer burden linked to overweight and obesity in the Nordic countries and estimate the potential for cancer prevention.

METHODS

Under different prevalence scenarios of overweight and obesity, the number of cancer cases in the Nordic countries in the next 30 years (i.e. 2016-2045) was estimated for 13 cancer sites and compared to the projected number of cancer cases if the prevalence stayed constant. The Prevent macro-simulation model was used.

RESULTS

Over the period 2016-2045, 205,000 cancer cases out of the 2.1 million expected for the 13 cancer sites (9.5%) that have been studied, could be avoided in the Nordic countries by totally eliminating overweight and obesity in the target population. The largest proportional impact was found for oesophageal adenocarcinoma (24%), and the highest absolute impact was observed for colon (44638) and postmenopausal breast cancer (41135).

CONCLUSION

Decreased prevalence of overweight and obesity would reduce the cancer burden in the Nordic countries. The results from this study form an important step to increase awareness and priorities in cancer control by controlling overweight and obesity in the population.

Cancer risk by education in Iceland; a census-based cohort study

Earlier studies have shown that cancer risk is related to educational level in many countries. The relationship between education and cancer risk has not been studied in the small, but ethnically homogenous, Icelandic population postulated to be outstanding as regards social equity.

MATERIAL AND METHODS

We conducted a follow-up study of a cohort of 60,194 males and 58,505 females aged 20-64 at census 1981 in Iceland. Information on education from the census was classified into three educational groups and linked with the population-based Icelandic Cancer Registry. Standardized incidence ratios (SIRs) were calculated for the period 1982 to 2004.

RESULTS

We found a significant association between educational level and cancer risk. Among males with academic education, the SIR was elevated for prostate cancer (SIR=1.17, 95% CI 1.05-1.30) and melanoma (SIR=1.41, 95% CI 1.00-1.93) and lowered for cancers of the lung (SIR=0.72, 95% CI 0.59-0.87) and stomach (SIR=0.67, 95% CI 0.48-0.90). Women with academic education had an increased risk of breast cancer (SIR=1.19, 95% CI 1.07-1.33) and a decreased risk of lung cancer (SIR=0.49, 95% CI 0.36-0.65). Increasing educational level was associated with a lowered risk of cervical cancer (p trend=0.017).

DISCUSSION

The association between education and cancer incidence seen in this study resembles observations from other countries and probably reflects concordance between social status and certain risk factors for cancer. Our study confirms health-related socioeconomic differences in Iceland and must be taken into account when programmes for health promotion are planned.

Epidemiological trends in oesophageal cancer in the Nordic countries

OBJECTIVE

The incidence rates of oesophageal cancer vary more than those of any other cancer, world-wide. The aim of this study was to examine the epidemiological features of oesophageal cancer in the Nordic countries.

MATERIAL AND METHODS

Epidemiological data from the Nordic Cancer Registry (NORDCAN Database, http://www.ancr.nu/nordcan.asp) were used for the study analysis.

RESULTS

From 1971 to 2000 in the Nordic countries, 18,034 oesophageal cancers were detected in males and 8216 in females. In males, the incidence rates (world age standardized incidence per 100,000) of oesophageal cancer in 1971-75 and 1996-2000 were 2.7 and 6.0 in Denmark, 4.2 and 3.2 in Finland, 3.4 and 5.6 in Iceland, 2.6 and 3.3 in Norway, and 2.9 and 3.3 in Sweden, respectively. In females, the corresponding figures were: Denmark 1.1 and 1.8, Finland 3.1 and 1.3, Iceland 2.5 and 1.3, Norway 0.7 and 0.9, and Sweden 1.1 and 1.0. Each Nordic country showed a significant geographical variation in the incidence of oesophageal cancer. In both males and females the incidence curves began rising after 40 years of age, but significantly more steeply in males than in females. Over the study period, oesophageal cancer mortality increased from 2.97 to 3.68 per 100,000 in males but decreased from 1.30 to 1.08 in females. The incidence rates of oesophageal adenocarcinoma increased in males in all Nordic countries, and the increase was most marked in Denmark. The incidence of oesophageal adenocarcinoma also increased among Danish females, but compared with males, the incidence rate remained significantly lower.

CONCLUSIONS

The time trends in incidence of oesophageal cancer differ between the Nordic countries, and there has also been geographical variation within them. On a global comparison, the incidence rates of oesophageal cancer are low in the Nordic region. Oesophageal cancer is a male-predominant disease in all Nordic countries, and the incidence rates of oesophageal adenocarcinoma have increased in males and Danish females.

Weight change in adult life and health outcomes

OBJECTIVE

To investigate the relationship between weight change in adult life and subsequent mortality and cancer incidence in women.

RESEARCH METHODS AND PROCEDURES

In 1994 to 1995, all women (age range, 42 to 81) still under general practitioner observation in the United Kingdom's Royal College of General Practitioners Oral Contraception Study (n = 12,303) were sent a health survey asking about health and lifestyle issues, including current weight and weight at age 30. The main outcome measures were 6-year all-cause mortality and cancer incidence among different weight change deciles. Cox regression was used to calculate hazard ratios that were adjusted for: social class at recruitment, BMI at age 30, and age group, parity, smoking status, and hormone replacement therapy status in 1995.

RESULTS

Women who had been obese at age 30 were more likely to die and significantly more likely to develop cancer in the 6 years after the health survey than non-obese respondents. Women reporting weight gains between age 30 and 1995 were significantly less likely to die during the 6 years after the health survey than those with a stable weight, whereas those with weight loss did not fare any better than those in the stable-weight group.

DISCUSSION

Although obesity at young age was associated with subsequent mortality and cancer incidence, weight gain over a time period of 12 to 51 years appeared to be beneficial when compared with women with stable weight over the same time period. Further research is needed to confirm or refute our findings and to allow detailed examination of potential explanations for them.