Do declines in occupational physical activity contribute to population gains in body mass index? Tromsø Study 1974–2016

Abstract

ObjectiveTo examine whether occupational physical activity changes predict future body mass index (BMI) changes.MethodsThis longitudinal cohort study included adult participants attending ≥3 consecutive Tromsø Study surveys (examinations 1, 2 and 3) from 1974 to 2016 (N=11 308). If a participant attended >3 surveys, the three most recent surveys were included. Occupational physical activity change (assessed by the Saltin-Grimby Physical Activity Level Scale) was computed from the first to the second examination, categorised into persistently inactive (n=3692), persistently active (n=5560), active to inactive (n=741) and inactive to active (n=1315). BMI change was calculated from the second to the third examination (height being fixed at the second examination) and regressed on preceding occupational physical activity changes using analysis of covariance adjusted for sex, birth year, smoking, education and BMI at examination 2.ResultsOverall, BMI increased by 0.84 kg/m2 (95% CI 0.82 to 0.89). Following adjustments as described previously, we observed no differences in BMI increase between the occupational physical activity change groups (Persistently Inactive: 0.81 kg/m2, 95% CI 0.75 to 0.87; Persistently Active: 0.87 kg/m2, 95% CI 0.82 to 0.92; Active to Inactive: 0.81 kg/m2, 95% CI 0.67 to 0.94; Inactive to Active: 0.91 kg/m2, 95% CI 0.81 to 1.01; p=0.25).ConclusionWe observed no prospective association between occupational physical activity changes and subsequent BMI changes. Our findings do not support the hypothesis that occupational physical activity declines contributed to population BMI gains over the past decades. Public health initiatives aimed at weight gain prevention may have greater success if focusing on other aspects than occupational physical activity.

The bidirectional associations between leisure time physical activity change and body mass index gain. The Tromsø Study 1974–2016

“…We have previously reported on the association between occupational physical activity and BMI change in a population-based cohort (The Tromsø Study) from Norway followed through repeated examinations every ~6 years. Our results suggested that occupational physical activity declines did not contribute to population BMI gains (40). As large proportions of the population are inactive during work hours (41,42), leisure time physical activity may have greater potential to prevent weight gain.…”

Occupational physical activity trends from 1987 to 2017: A nationally representative sample of 160,509 Spanish adults

“…Thus, other minor occupational activities may have been dismissed. Moreover, OPA prevalence may partially stem from individuals whose primarily activity correspond to education or household chores instead of work‐related tasks, although a wide notion of OPA, including the three has been used in prior research (Sagelv, Ekelund, & Hopstock, 2021). Despite this, it is expected that trends would remain similar even when strictly considering physical activity at work solely due to the high percentage of workers comprising the samples; therefore, a uniform information bias is assumed, which gives us confidence on our estimates.…”

Occupational physical activity and risk of mortality in women and men: the Tromsø Study 1986–2021

“…Physical activity was self-reported with the Saltin-Grimby Physical Activity Level Scale (SGPALS),37 38 which was slightly modified in the Tromsø Study compared with the original37 (described elsewhere39). Participants ranked their physical activity level according to four mutually exclusive levels of OPA and LTPA (table 1).…”

“…In Tromsø4 , the leisure time SGPALS was replaced by the Cohort of Norway physical activity questionnaire (43) (Supplementary Table S1), which we harmonized to the SGPALS (25) (Supplementary Table S2). (39).…”