Abstract

Background Obesity among firefighters can present a hindrance to operational effectiveness. In North American studies, 80% of US firefighters are overweight or obese. No studies have explored obesity among firefighters in the UK, and it is unclear whether obesity is a problem among UK firefighters.

Aims To establish the prevalence of obesity among a large sample of firefighters in the UK and to explore changes in body mass index (BMI) over a 3-year period.

Methods The BMI and body composition of 735 male firefighters from a UK county fire and rescue service were assessed in 2008 and 2011.

Results In 2008, 65% of the firefighters were either overweight (54%) or obese (11%). In 2011, slightly fewer firefighters were overweight (53%), but the proportion classified as obese increased significantly to 13%. Those classified as normal weight in 2008 were more likely to have gained weight by 2011 in comparison with those categorized as obese at baseline. A lower proportion of firefighters were classified as high risk for obesity based on their waist circumference in 2008.

Conclusions The proportion of firefighters who are either overweight or obese is lower in this UK sample than that found in US studies. Nevertheless, the proportion of UK firefighters classed as overweight was higher than that found in the general population samples from England. Given the negative implications of obesity for performance, there is a need for further investment in theory-based, sector-specific health promotion research and practice.

Introduction

Firefighters are expected to maintain high levels of physical fitness [1]. However, US evidence suggests that firefighters struggle to maintain fitness levels [2,3]: 73–88% of US firefighters are overweight or obese [2–4]. Obesity can negatively impact firefighters’ safety at work, their overall well-being and their work productivity [2, 4–8].

The prevalence of obesity among UK firefighters is unknown. Although there is no statutory requirement for fitness tests, guidance recommends that firefighters should have their weight, body mass index (BMI) and waist circumference (WC) assessed periodically [1]. Those with BMI > 27 kg/m2 should be advised to lose weight. This longitudinal study examines body weight and composition in a cohort of UK firefighters.

Methods

Data were collected from a UK county fire and rescue service comprising 40 stations. Assessments were carried out by occupational health personnel. Ethics committee approval was gained from the Institute of Work, Health and Organisations, University of Nottingham.

Operationally active firefighters undergoing annual health assessments in 2008 and 2011 were included in the study. Body weight (kg) and height (cm) were measured using electronic weighing scales (Seca, UK) and a stadiometer. BMI was calculated as kg/m2. WC was measured around the umbilicus to the nearest 0.5 cm using anthropometry tape. Body fat percentage (BF%) was measured using the Omron® BF 306 body fat monitor (Omron Matsusaka Co., Ltd). Age and employment type were recorded for each firefighter.

BMI data were used as a continuous variable and recoded into categories: normal weight (18.5–24.9 kg/m2), overweight (25.0–29.9 kg/m2) and obese (≥30.0 kg/m2) [9]. We dichotomized BMI using a cut-off of ≥27 kg/m2 defined by the guidelines [1] as the threshold for intervention.

Chi-square tests were performed to examine change over time in the proportion of firefighters in each BMI category. A 2 (time) × 3 (2008 BMI category) mixed analysis of covariance (ANCOVA) examined the effects of BMI on body composition over time (BF% and WC). The analyses were repeated with the dichotomous measures of BMI (2 × 2 mixed ANCOVA). In each analysis, we controlled for mean age and employment type.

Results

A total of 1232 employees took part in the 2008 annual health assessment (90% participation rate). There were 877 operationally active firefighters assessed in 2008 and 2011 (71% of the 2008 cohort). In all, 121  firefighters were excluded for missing data. Female firefighters (n = 21) were also excluded, producing a sample of 735  male firefighters.

Participants’ mean baseline age was 37.6 years (SD = 8.5), 439 worked whole time and 296 were retained. In 2008, 35% firefighters were classified as normal weight, 54% overweight and 11% obese (Table 1). In 2011, the numbers categorized as normal weight and overweight fell to 34% and 53%, respectively. The proportion classified as obese (n = 95, 13%) increased significantly (x2 = 709, df = 4, P < 0.001). Of those classified as normal weight in 2008, 47 became overweight and 2 became obese in 2011. From the 2008 overweight category, 30 became obese, while 39 moved into the normal weight category. Sixteen firefighters classified as obese in 2008 became overweight, and one moved into the normal weight category in 2011.

Table 1:

BMI, BF% and WC measured in the 3 BMI groups in 2008 and 2011

 Baseline 2008 P Follow-up 2011 P 
 Normal BMI 18.5-24.9 (n = 257) Overweight BMI 25.0–29.9 (n = 398) Obese BMI ≥30 (n = 80)  Normal BMI 18.5–24.9 Overweight BMI 25.0–29.9 Obese BMI ≥30  
Mean BMI (kg/m2) (SD) 23.3 (1.3) 27.2 (1.4) 32.5 (2.3)  23.7 (1.8) 27.2 (1.8) 31.8 (3.0)  
Mean BF%a (SD) 17.2 (4.3) 23.7 (3.9) 30.4 (3.8) <0.001 17.9 (4.2) 23.5 (4.2) 29.6 (4.1) <0.001 
Mean WCa (cm) (SD) 84.9 (5.9) 93.4 (6.3) 104.4 (6.3) <0.001 86.0 (6.0) 93.7 (6.4) 105.4 (7.6) <0.001 
Mean ageb (years) (SD) 35.5 (9.2) 38.5 (8.0) 40.3 (7.8) <0.001 37.7 (9.1) 40.6 (8.0) 42.0 (7.9) <0.001 
Whole time employment n (%) 168 (38) 238 (54) 33 (8) <0.01 154 (35) 240 (55) 45 (10) <0.05 
Retained employment n (%) 88 (30) 160 (54) 48 (16) <0.01 94 (32) 152 (51) 50 (17) <0.01 
 Baseline 2008 P Follow-up 2011 P 
 Normal BMI 18.5-24.9 (n = 257) Overweight BMI 25.0–29.9 (n = 398) Obese BMI ≥30 (n = 80)  Normal BMI 18.5–24.9 Overweight BMI 25.0–29.9 Obese BMI ≥30  
Mean BMI (kg/m2) (SD) 23.3 (1.3) 27.2 (1.4) 32.5 (2.3)  23.7 (1.8) 27.2 (1.8) 31.8 (3.0)  
Mean BF%a (SD) 17.2 (4.3) 23.7 (3.9) 30.4 (3.8) <0.001 17.9 (4.2) 23.5 (4.2) 29.6 (4.1) <0.001 
Mean WCa (cm) (SD) 84.9 (5.9) 93.4 (6.3) 104.4 (6.3) <0.001 86.0 (6.0) 93.7 (6.4) 105.4 (7.6) <0.001 
Mean ageb (years) (SD) 35.5 (9.2) 38.5 (8.0) 40.3 (7.8) <0.001 37.7 (9.1) 40.6 (8.0) 42.0 (7.9) <0.001 
Whole time employment n (%) 168 (38) 238 (54) 33 (8) <0.01 154 (35) 240 (55) 45 (10) <0.05 
Retained employment n (%) 88 (30) 160 (54) 48 (16) <0.01 94 (32) 152 (51) 50 (17) <0.01 

BMI, body mass index; BF%, body fat percentage; WC, waist circumference; SD, standard deviation.

Categorical data analysed with chi-square test.

aControlling for age and employment type at baseline.

bControlling for employment type at baseline.

There were no significant overall changes in BF% and WC for the whole sample between 2008 and 2011. Significant between-participant effects for the BMI group for BF% [F(2, 730) = 360, P < 0.001] and WC [F(2, 730) = 349, P < 0.001] were found. There were significant interaction effects between time and BMI (2008) for BF% [F(2, 730) = 9.5, P < 0.001] and between time and BMI (2008) for WC [F(2, 730) = 7.4, P < 0.01]. Therefore, while overall averages for BF% and WC remained stable, 2008 BMI category predicted the amount of change over time. Firefighters within the 2008 normal weight category had a mean increase in BF% and WC in 2011. In contrast, these measures decreased on average in those categorized as obese. There were no significant changes in the overweight group. Using dichotomized measures of BMI, the ANCOVA showed significant interaction effects for BF% [F(1, 731) = 10.6, P < 0.01] and WC [F(1, 731) = 8.3, P < 0.01] (Table 2).

Table 2

: BMI, BF% and WC measured in those with a BMI ≤⃒26.9 (n = 442) and those with BMI ≥27 (n = 293)

 Baseline 2008 Follow-up 2011 P 
 BMI ≤⃒26.9 BMI ≥27.0 BMI ≤⃒26.9 BMI ≥27.0  
Mean BMI (kg/m2) (SD) 24.4 (1.7) 29.5 (2.3) 24.7 (1.9) 29.2 (2.6)  
Mean BF%a (SD) 19.3 (4.8) 26.5 (4.2) 19.6 (4.7) 26.0 (4.6) <0.001 
Mean WCa (cm) (SD) 87.3 (6.3) 98.7 (8.0) 88.2 (6.3) 98.5 (7.8) <0.05 
 Baseline 2008 Follow-up 2011 P 
 BMI ≤⃒26.9 BMI ≥27.0 BMI ≤⃒26.9 BMI ≥27.0  
Mean BMI (kg/m2) (SD) 24.4 (1.7) 29.5 (2.3) 24.7 (1.9) 29.2 (2.6)  
Mean BF%a (SD) 19.3 (4.8) 26.5 (4.2) 19.6 (4.7) 26.0 (4.6) <0.001 
Mean WCa (cm) (SD) 87.3 (6.3) 98.7 (8.0) 88.2 (6.3) 98.5 (7.8) <0.05 

BMI, body mass index; BF%, body fat percentage; WC, waist circumference; SD. standard deviation.

a2 × 2 mixed ANCOVA, controlling for age and employment type at baseline.

Discussion

Firefighters in 2008 were overweight (54%) or obese (11%). In 2011, the proportion of overweight firefighters fell slightly (53%), while the proportion classified as obese increased significantly (13%). Study strengths included the longitudinal design, but generalizability was limited by restricting the study to firefighters within one UK region. Differences in the way anthropometric measures were taken by different occupational health personnel may have also impacted the results.

The prevalence of overweight/obesity in 2008 and 2011 (65% and 66%) in UK firefighters is lower than the prevalence of overweight/obesity in US firefighters (73–88%) [2–5]. UK firefighters may not have the same health and fitness issues as US firefighters, which may be due to general population differences.

The proportion of firefighters classified as normal weight in 2008 (35%) was similar to that (34%) reported in a general population sample of adult males in UK [10]. A greater proportion of firefighters were classified as overweight (54%) compared with this population (42%); however, fewer were classified as obese (11% versus 24%) [10]. Approximately, 34% of men in England had a WC >102 cm in 2008 [10] compared with 11% of the firefighters. This suggests that despite a higher prevalence of firefighters classified as overweight, a lower proportion are classified as high risk based on their WC. This highlights the importance of measuring both BMI and WC in populations with higher levels of lean tissue.

Male firefighters classified as normal weight in 2008 were likely to gain weight over time. In contrast, firefighters classified as obese in 2008 were likely to lose weight over time. Although the findings are significant, the average change in weight is small and suggests that body composition is fairly stable in firefighters. This suggests that those with obesity could be benefitting from advice on losing weight from occupational health personnel. For those classified as normal weight, it is unclear whether weight gain is due to body fat or muscle gain. Further research is required.

This study provides an indication of the prevalence of obesity among UK firefighters and provides a benchmark for occupational health staff across UK fire and rescue services.

Key points
  • This is the first study to present data on the prevalence of overweight and obesity among UK firefighters.

  • A greater proportion of UK firefighters are overweight when compared to nationally representative data although the proportion of firefighters classed as obese was lower.

  • The findings could contribute to the development of an evidence base to support the prioritization of firefighters’ health and fitness initiatives.

Acknowledgements

We would like to thank JA for his help and the county fire and rescue service (who do not wish to be identified) for participating in this study.

Funding

This work was supported by a county fire and rescue service.

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