In a recently published study, Dr obesityResearchers evaluated associations between body mass index (BMI) and new-onset site-specific tumors in young men to estimate population-attributable fractions (PAFs) due to BMI, according to predicted trends in obesity.
Study: Association between BMI in youth and site-specific cancer in men – a cohort study with register linkage. Image credit: oatawa/Shutterstock.com
The International Agency for Research on Cancer (IARC) has linked obesity to tumors of the esophagus, gastric cardia, colon and rectum, liver, gallbladder, pancreas, kidney, thyroid, and multiple myeloma in men.
However, evidence for associations in adolescents and young adults is limited, although it is generally consistent with findings in older adults. Further investigation may inform obesity prevention and management across the ages.
About the study
In a population-based cohort study, researchers evaluated the relationship between body mass index and site-specific tumor incidence in young men, accounting for cardiorespiratory fitness (CRF) and smoking status.
They determined tumor site-specific PAF in obese and overweight men based on past and current trends in obesity and overweight in Swedish and United States (US) youth.
Weight and height were assessed at age 18 in a Swedish national observational study to calculate BMI, and people were classified as underweight (less than 18.5 kg per m2), overweight (between 25 and 29.9 kg per m2), or obese. . (equal to or greater than 30 kg per m2).
From 1968 to 2005, male participants aged 16 to 25 participated in the recruitment experiment. Individuals who were diagnosed with a tumor five years before or within five years of military enlistment and died or emigrated within five years were excluded.
The Swedish Military Service Description record was used to identify conscripts. Tumor diagnostic data were obtained from the Swedish National Patient Registry and Cause of Death Register. International Classification of Diseases, eighth, ninth, and tenth revisions (ICD-8, 9, and 10) codes were used to designate site-specific tumors.
At recruitment, CRF data were assessed as maximal aerobic exertion in a cycle ergometer test. Study participants were tracked until they were diagnosed with a tumor, died, first emigrated after recruitment, or discontinued the study on December 31, 2019, whichever occurred first.
Cox proportional hazards regression modeling was used to calculate hazard ratios (HRs) for linear relationships for BMI, age, year, employment position and parental educational level as variables.
Furthermore, sensitivity analyzes were performed to investigate confounding factors such as cardiorespiratory fitness and smoking status. In addition, an ad hoc sensitivity analysis was performed to assess the effect of cognitive status on outcomes.
Primary analysis included 1,489, 115 men; The average age of participants at recruitment was 18 years, and the average BMI was 22, with two percent of individuals having a BMI of 30 or greater.
Obesity has increased slowly over time, from one percent between 1968 and 1979 to four percent between 1990 and 2005, with an increasing trend for body mass index below 20, an increasing trend for body mass index 25 and above, and a steady trend for body mass 20 and above. Index between 24.9.
Obese men are more likely to have high blood pressure, poorer cognitive ability and less educated parents than their peers. Underweight and obese men showed a higher likelihood of smoking and had poorer cardiorespiratory fitness than their normal weight peers.
During 31 years of follow-up (average) 78,217 individuals developed tumors. The average participant age at tumor diagnosis ranged from 39 years (Hodgkin lymphoma) to 59 years (prostate tumor).
BMI showed linear associations with site-specific incidence for all 18 assessed (leukemia; malignant melanoma; Hodgkin lymphoma; myeloma; non-Hodgkin-tumor type lymphoma; and tumors of the head and neck, lung, thyroid system (CNS nervous) ), stomach, esophagus, liver, gallbladder, pancreas, rectum, colon, bladder and kidney), in some cases evident in body mass index values that usually indicate normal-range weight (between 20 and 25 kg per m2).
A greater BMI was associated with reduced prostate tumor risk. Some gastrointestinal malignancies have the highest HR and PAF.
Smoking was associated with a reduced risk of prostate tumors and malignant melanoma, but an increased risk of tumors at various sites, including the head and neck, esophagus, lung, pancreas, stomach, liver, urinary bladder, and gallbladder. Adjusted for cardiorespiratory fitness, the association between body mass index and tumor risk was enhanced.
After CRF adjustment, the most severe confounders by cardiorespiratory fitness were identified for lung tumors in underweight men. HR values for obesity and overweight are increased for several tumor sites, especially gastrointestinal malignancies.
A higher BMI was associated with a greater risk of tumors in men with low CRF for tumors at many sites, including head and neck, stomach, esophagus, liver, bladder, kidney, colon, as well as Hodgkin lymphoma. CRF status in recruitment.
Associations between body mass index and tumors of the central nervous system, pancreas, thyroid, and leukemia were stronger in men with moderate to high CRF than those with low cardiorespiratory fitness.
Cognitive ability and muscle strength adjustment at admission did not affect outcomes. Based on the current and historical prevalence of adolescent obesity and overweight in the United States and Sweden, PAF was superior for gastrointestinal tumor locations.
Overall, study results support the IARC-reported links between greater BMI in adults and higher risk of site-specific malignancies, including tumors in various organs, and demonstrate that these associations were independent of CRF.
Furthermore, studies have found an association between childhood BMI and the risk of developing leukemia, myeloma, Hodgkin lymphoma, non-Hodgkin lymphoma, and tumors in pulmonary tissue, urinary bladder, and CNS.
Findings include PAF estimates that take into account the global obesity epidemic. If current trends continue, immediate steps should be taken to address the obesity epidemic and prepare the health care system for an increase in tumor cases.