Adiposity, physical activity and risk of diabetes mellitus: Prospective data from the population-based HUNT study, Norway

Background Physical activity may counteract the adverse effects of adiposity on cardiovascular mortality; however, the evidence of a similar effect on diabetes is sparse. This study examines whether physical activity may compensate for the adverse effect of adiposity on diabetes risk. Methods The study population consisted of 38 231 individuals aged 20 years or more who participated in two consecutive waves of the prospective longitudinal Nord-Trøndelag Health Study in Norway: in 1984–1986 and in 1995–1997. A Poisson regression model with SEs derived from robust variance was used to estimate adjusted risk ratios of diabetes between categories of body mass index and physical activity. Results Risk of diabetes increased both with increasing body mass (Ptrend <0.001) and with decreasing physical activity level (Ptrend <0.001 in men and 0.01 in women). Combined analyses showed that men who were both obese and had low activity levels had a risk ratio of 17 (95% CI 9.52 to 30) compared to men who were normal weight and highly active, whereas obese men who reported high activity had a risk ratio of 13 (95% CI 6.92 to 26). Corresponding analysis in obese women produced risk ratios of 15 (95% CI 9.18 to 25) and 13 (95% CI 7.42 to 21) among women reporting low and high activity levels, respectively. Conclusions This study shows that overweight and obesity are associated with a substantially increased risk of diabetes, particularly among those who also reported being physically inactive. High levels of physical activity were associated with a lower risk of diabetes within all categories of body mass index, but there was no clear evidence that being physically active could entirely compensate for the adverse effect of adiposity on diabetes risk

Cancer incidence in non-immigrants and immigrants in Norway

Background Major cancers are associated with lifestyle, and previous studies have found that the non-immigrant populations in the Nordic countries have higher incidence rates of most cancers than the immigrant populations. However, rates are changing worldwide – so these differences may disappear with time. Here we present recent cancer incidence rates among immigrant and non-immigrant men and women in Norway and investigate whether previous differences still exist. Material and methods We took advantage of a recent change in the Norwegian Cancer Registry regulations that allow for the registry to have information on country of birth. The number of person years for 2014–2018 was aggregated for every combination of sex, five-year age-group and country of birth, by summing up each year’s population in these groups. The number of cancer cases was then counted for the same groups, and age-standardised incidence rates calculated by weighing the age-specific incidence rates by the Nordic and World standard populations. Further, we calculated incidence rate ratios using the non-immigrant population as a reference. Results Immigrants from Eastern Europe, the Middle East, Africa and Asia had lower incidence of total cancer compared to the non-immigrant population in Norway and immigrants born in the other Nordic or high-income countries. However, some cancers were more common in certain immigrant groups. Asian men and women had threefold the incidence of liver cancer than non-immigrant men and women. Men from the other Nordic countries and from Eastern Europe had higher lung cancer rates than non-immigrant men. Conclusion National registries should continuously monitor and present cancer incidence stratified on important population subgroups such as country of birth. This can help assess population subgroup specific needs for cancer prevention and treatment, and could eventually help reduce the morbidity and mortality of cancer

Breast cancer-specific survival by clinical subtype after 7 years follow-up of young and elderly women in a nationwide cohort

Age and tumor subtype are prognostic factors for breast cancer survival, but it is unclear which matters the most. We used population‐based data to address this question. We identified 21,384 women diagnosed with breast cancer at ages 20–89 between 2005 and 2015 in the Cancer Registry of Norway. Subtype was defined using estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor 2 (HER2) status as luminal A‐like (ER+PR+HER2‐), luminal B‐like HER2‐negative (ER+PR‐HER2‐), luminal B‐like HER2‐positive (ER+PR+/‐HER2+), HER2‐positive (ER‐PR‐HER2+) and triple‐negative (TNBC) (ER‐PR‐HER2‐). Cox regression estimated hazard ratios (HR) for breast cancer‐specific 7‐year survival by age and subtype, while adjusting for year, grade, TNM stage and treatment. Young women more often had HER2‐positive and TNBC tumors, while elderly women (70–89) more often had luminal A‐like tumors. Compared to age 50–59, young women had doubled breast cancer‐specific mortality rate (HR = 2.26, 95% CI 1.81–2.82), while elderly had two to five times higher mortality rate (70–79: HR = 2.25, 1.87–2.71; 80–89: HR = 5.19, 4.21–6.41). After adjustments, the association was non‐significant among young women but remained high among elderly. Young age was associated with increased breast cancer‐specific mortality among luminal A‐like subtype, while old age was associated with increased mortality in all subtypes. Age and subtype were strong independent prognostic factors. The elderly always did worse, also after adjustment for subtype. Tumor‐associated factors (subtype, grade and stage) largely explained the higher breast cancer‐specific mortality among young. Future studies should address why luminal A‐like subtype is associated with a higher mortality rate in young women

Ethnic differences in the incidence of cancer in Norway

Traditionally there have been differences in cancer incidence across geographic regions. When immigrants have moved from low‐income to high‐income countries, their incidence have changed as they have adapted to the lifestyle in the new host country. Given worldwide changes in lifestyle factors over time, we decided to examine cancer incidence in immigrant groups in Norway, a country with a recent immigration history, complete cancer registration and universal public health care. We linked immigration history for the complete population to information on cancer diagnosis from the Cancer Registry of Norway for the period 1990–2012. Age‐standardized (world) overall and site‐specific cancer incidence were estimated for different immigrant groups and compared to incidence among individuals born in Norway. Among 850,008 immigrants, 9,158 men and 10,334 women developed cancer, and among 5,508,429 Norwegian‐born, 263,316 men and 235,020 women developed cancer. While incidence of breast and colorectal cancer were highest among individuals born in Norway and other high‐income countries, other cancer types were higher in immigrants from low‐income countries. Lung cancer incidence was highest in Eastern European men, and men and women from Eastern Europe had high incidence of stomach cancer. Incidence of liver cancer was substantially higher in immigrants from low‐income countries than in individuals born in Norway and other high‐income countries. Our results mirror known cancer challenges across the world. Although cancer incidence overall is lower in immigrants from low‐income countries, certain cancers, such as lung, liver and stomach cancer, represent major challenges in specific immigrant groups