Lifelong differences in cancer incidence and mortality between subgroups of similar socioeconomic status in the Royal Norwegian Navy.

OBJECTIVES: In a previous cohort study of 28 300 Navy servicemen, vessel crews showed higher cancer incidence and mortality than did land-based personnel. We have extended the follow-up to look for changes in cancer risk, and to explore temporal trends in cancer incidence and cancer mortality during more than six decades of follow-up. METHODS: Cancer incidence and total cancer mortality were compared with the general population by calculating standardised ratios (standardised incidence ratios (SIRs), standardised mortality ratios) for the entire follow-up, with temporal trends through seven consecutive 10-year time spans from individual entry to follow-up. Rates were compared between the subgroups using Poisson regression, expressed as rate ratios (RRs). RESULTS: Cancer incidence in Navy servicemen suggested a healthy soldier effect limited to the first three decades of follow-up and confined to land-based personnel. Overall, vessel crews showed 13% higher cancer incidence and 36% higher cancer mortality than other Navy servicemen. Some of the differences may be explained by a higher risk in vessel crews of cancers known to have less than 25% 5-year relative survival (RR=1.71), such as cancers of the lung, liver, pancreas and mesothelioma. CONCLUSION: Through most of the observation time, vessel crews had an overall cancer SIR that was higher than that of land-based personnel. Much of this excess involved cancers with a generally poor prognosis, linked to lifestyle and work environment. The contrasts in cancer incidence and mortality between the two subgroups of Navy servicemen persisted through more than six decades.

Cause-Specific Mortality Among Norwegian Veterans Deployed to Afghanistan Between 2001 and 2019.

INTRODUCTION: Norwegian military forces participated in the military campaign Operation Enduring Freedom in Afghanistan starting in 2001. Military personnel often show a "healthy soldier effect" in terms of lowered all-cause mortality when compared to the general population. However, military service in conflict areas is associated with an increased risk of death from external causes such as transport accidents and suicide after discharge. We aimed to investigate cause-specific mortality in a cohort of 9,192 Norwegian (7.5% women) veterans deployed to Afghanistan between 2001 and 2019. MATERIALS AND METHODS: We followed cohort members from their first day of service in Afghanistan through 2019. We computed standardized mortality ratios (SMRs) with 95% CIs by comparing the observed number of deaths in our cohort with the expected number of deaths in the general population. Standardized mortality ratios were calculated for the full follow-up period among men and women separately, and among men only for two time periods: during deployment and after discharge from service in Afghanistan. RESULTS: We observed 77 deaths (3 women and 74 men), 10 of which occurred during deployment (war casualties, 1 woman and 9 men); all others occurred after discharge. All-cause mortality in women did not differ from that in the general population (SMR = 0.52, 95% CI 0.11-1.53). For men, the observed all-cause mortality was lower than the expected rate for the full follow-up period (SMR = 0.55, 95% CI 0.43-0.69), during deployment, and after discharge, while deaths because of transport accidents after discharge (13 cases) were more than twice as high as expected rates (SMR = 2.36, 95% CI 1.26-4.04). The 11 observed suicides gave a nonstatistically significant, lower suicide risk compared to the expected rates (SMR = 0.66, 95% CI 0.33-1.18). CONCLUSION: In accordance with the "healthy soldier effect," military service in Afghanistan was generally associated with a lower than expected risk of death both during deployment and after discharge. The risk of death from transport accidents was higher than expected after discharge, while the observed incidence of suicide did not differ from the expected rate in the general population.

The Norwegian Armed Forces Health Registry conscription board health examinations 1968-2018.

Aim: The aim of the study is to encourage further research initiatives and collaborations based on Norwegian Armed Forces Health Registry (NAFHR) data by presenting basic information on the data contained therein. Methods: We describe how conscription board health examinations (CBHEs) are carried out, how results are recorded in the NAFHR, and the completeness of NAFHR data that are electronically available for research purposes. Results: In December 2018, the NAFHR contained data on nearly 1.5 million Norwegian citizens (95% men) who attended CBHE in 1968-2018 at the age of 17-19 years. The percentage of persons included from each birth cohort has varied as the Armed Forces' personnel requirements and filing procedures have changed, increasing from 73% of eligible men born in 1950 to 95% of eligible men born in 1960-1991. In 2010 a preselection of candidates was implemented wherefore less than half of men born in 1992-2000 are registered in the NAFHR. Information on aerobic fitness, cognitive general ability, height and weight is registered for approximately 95% of individuals included in the NAFHR. The NAFHR contains more detailed health information for CBHEs that took place as from 1980, and information included from 2011 onwards is the most detailed. Unique, national personal identification numbers may be used to link the NAFHR to other health registries or data sources for public health research. Conclusions: The NAFHR contains CBHE data on the majority of Norwegian men and a substantial number of women born since 1950. NAFHR data represent a valuable resource for research collaborations.

Cancer incidence and all-cause mortality among civilian men and women employed by the Royal Norwegian Navy between 1950 and 2005.

OBJECTIVE: We aimed to investigate cancer incidence and all-cause mortality in a cohort of 8358 civilians (5134 men and 3224 women) employed by the Royal Norwegian Navy at any time between 1950 and 2005. METHODS: The cohort was followed for cancer incidence and all-cause mortality from 1960 through 2015. Standardised incidence ratios (SIR) and mortality ratios (SMR) were calculated from national rates. Separate SIRs were calculated for a subgroup of male workshop workers and another of female cleaners. RESULTS: Overall cancer incidence among men was similar to the reference rate; male breast cancer was more frequent (SIR = 3.23). Male workshop workers showed a SIR of 1.77 for stomach cancer, while their incidence of lympho-haematopoietic cancers was half that of the reference rates. Women had increased risks of overall cancer (SIR = 1.11), lung cancer (SIR = 1.35), and ovarian cancer (SIR = 1.39). Female cleaners showed a SIR of 2.33 for bladder cancer and a lowered incidence of brain cancer (SIR = 0.18). In the overall cohort, all-cause mortality was lower than expected for men (SMR = 0.92) and closer to the reference rate for women (SMR = 0.95). CONCLUSION: In men, we observed a lowered all-cause mortality and an excess of stomach cancer in workshop workers. In women, increased risks of overall cancer, lung cancer and ovarian cancer was seen. An increased risk of bladder cancer and a lowered incidence of brain cancer was observed among female cleaners.

Flicker VEPs reflecting multiple rod and cone pathways.

In an attempt to determine whether the relative contributions of magno-mediated and parvo-mediated inputs to the cortex are significantly altered in the transition from cone to rod vision, VEPs were recorded at different luminance levels (photopic to scotopic) for 2Hz square-wave, isochromatic flicker. The VEP mass response appears capable of reflecting major parvo-mediated contributions even at luminance levels for which responses from individual cells in the parvocellular pathway are reported to be weak. Our findings suggest that parvo-mediated responses are the dominant source of high-contrast isochromatic flicker VEPs at all light levels.

Visual evoked potentials for red-green gratings reversing at different temporal frequencies: asymmetries with respect to isoluminance.

Human visual evoked potentials (VEPs) were recorded for abrupt reversals of 2 cycles/deg (c/deg) square-wave gratings combining high red-green contrast with different levels of luminance contrast. Response characteristics--2nd harmonic amplitudes and peak latencies as a function of luminance contrast--were compared for four different reversal rates ranging from 6.25 Hz to 12.5 Hz. At every reversal frequency, the VEP amplitude and latency plots were nonsymmetrical with respect to isoluminance. The amplitude dropped to a minimum within a region of rapid phase change, always at a red-green luminance contrast for which the green color had the higher luminance, at about 40% or 50% Michelson luminance contrast. The rapid phase shift around this contrast suggested a sudden change in the relative impact of VEP generators with different latencies, possibly dominated by parvocellular or magnocellular input. The most prominent VEP waveform through most of the luminance contrast range, P110, is interpreted in terms of a parvo-mediated response that is attenuated with increasing reversal frequency. Contrast-dependent changes in the P110 amplitude appear to be responsible for the VEP asymmetries reported here.

Visual evoked potentials for reversals of red-green gratings with different chromatic contrasts: asymmetries with respect to isoluminance.

Human visual evoked potentials (VEPs) were recorded for abrupt 6.25-Hz reversals of 2 c/deg square-wave gratings combining red-green contrast with different levels of luminance contrast. Response characteristics-- amplitudes and peak latencies as a function of luminance contrast--were compared for four different pairs of red-green colors and an isochromatic yellow grating. For each of the red-green color pairs, the plots of VEP amplitudes and latencies were nonsymmetrical with respect to isoluminance. The amplitude dropped to a minimum within a region of rapid phase change, at a different contrast for each color pair but always at a luminance contrast for which the greener color had the higher luminance. When the contrast-response curve for each of the four red-green pairs was modeled by a simple |CL - CM| opponency of L- and M-cone contrast using a fixed CL/CM weighting ratio of about two, there was a close correspondence between the contrast giving a null in the modeled response and that giving a minimum in the VEP amplitude. So for the stimulus parameters applied here, the reversal VEP appeared to be dominated by L/M-opponent response contributions for which the signed CL/CM-cone weighting ratio was close to a value of minus two rather than to a value of minus one, which is characteristic of the psychophysical red-green detection mechanism and representative of CL/CM weighting ratios for precortical cells in the parvocellular pathway.