Height, body mass index and prostate cancer risk and mortality by way of detection and cancer risk category

Abstract

Obesity is a risk factor for advanced, but not localised, prostate cancer (PCa), and for poor prognosis. However, the detection of localised PCa through asymptomatic screening might influence these associations. We investigated height and body mass index (BMI) among 431 902 men in five Swedish cohorts in relation to PCa risk, according to cancer risk category and detection mode, and PCa-specific mortality using Cox regression. Statistical tests were two-sided. Height was positively associated with localised intermediate-risk PCa (HR per 5 cm, 1.03, 95% CI 1.01-1.05), while overweight and obesity were negatively associated with localised low-and intermediate-risk PCa (HRs per 5 kg/m 2 , 0.86, 95% CI 0.81-0.90, and 0.92, 95% CI 0.88-0.97). However, these associations were partially driven by PCa's detected by asymptomatic screening and, for height, also by symptoms unrelated to PCa. The HR of localised PCa's, per 5 kg/m 2 , was 0.88, 95% CI 0.83 to 0.92 for screen-detected PCa's and 0.96, 95% CI 0.90 to 1.01 for PCa's detected through lower urinary tract symptoms. BMI was positively associated with PCa-specific mortality in the full population and in case-only analysis of each PCa risk category (HRs per 5 kg/m 2 , 1.11-1.22, P for heterogeneity = .14). More active health-seeking behaviour among tall and normal-weight men may partially explain their higher risk of localised PCa. The higher PCa-specific mortality among obese men across all PCa risk categories in our study suggests obesity as a potential target to improve the prognosis of obese PCa patients. K E Y W O R D S body mass index, body size, height, observational research, prostate cancer 1 | INTRODUCTION Obesity is an established risk factor for several cancer forms, 1 but the association with prostate cancer (PCa) is complex. While high body mass index (BMI), a marker of general obesity, has been negatively

Waist circumference and a body shape index and prostate cancer risk and mortality

“…Despite the lack of an association between BMI and more advanced PCa in our previous study, 5 we, and a large number of other studies, found a positive association between BMI and the risk of PCa‐specific mortality 6,18‐22 . Only a few studies reported findings for WC and PCa‐specific mortality, which varied from no association 23,24 to a positive association 3,6 .…”

“…Moreover, more active screening behaviour in normal weight men compared to men with obesity may be involved. In our aforementioned study, we found that the negative association between BMI and the risk of localised PCa was partially driven by PCa cases detected through asymptomatic testing, 5 which supports a role for detection bias in the obesity–PCa association. To the best of our knowledge, no other prospective study has tested the prevailing hypothesis that the negative association between adiposity and the risk of localised PCa may be partly driven by localised PCa cases detected through PSA‐testing.…”

“…In most previous observational studies, body mass index (BMI), a marker of general obesity, has been found to be negatively associated with the risk of localised PCa, and positively associated with advanced PCa risk 2‐4 . However, in our recent study including 32,871 incident PCa cases 5 and another large pooled analysis by Genkinger et al, 6 only little evidence was found for an association between BMI and the risk of more advanced PCa. Also, findings from Mendelian randomisation studies suggest no strong evidence of a causal effect of BMI on PCa 7,8 .…”

“…Out of the five cohorts included in our original investigation of general obesity and PCa, 5 the Swedish Construction Workers Cohort [CWC] (‘Bygghälsan’), 28 the Västerbotten Intervention Programme [VIP], 29,30 the Northern Sweden Monica [MONICA] study, 29,31 the Malmö Diet and Cancer Study [MDCS] 32 and the Malmö Preventive Project [MPP], 33 WC had been measured in all but the largest cohort, the CWC, and only during later years in the VIP (2003 onwards), and during a re‐examination period (2002–2006) in the MPP. In all cohorts, height, weight and WC were measured at a health examination by trained staff.…”

“…After excluding examinations: from duplicate cohorts in men who had participated in more than one cohort, performed before 18 years of age, with a prevalent cancer (excluding non‐melanoma skin cancer), with mismatching dates, and with missings for WC, height or weight, a total of 58,457 men were included in the study, comprising approximately 15% of the population in our previous study 5 …”