MATERIALS AND METHODS

Ethical approval: This study was conducted with the approval of the Veteran Affairs Department, Malaysian Armed Forces. An approval letter to conduct this study was also obtained from the Medical Research and Innovation Secretariat Committee, Counsellor Tuanku Mukhriz Hospital (reference number: UKM PPI/111/8/JEP-2017-708).

Subject and study location: A cross-sectional study was carried out with randomly selected respondents based on a registered list as members of the Department of Veteran Affairs Malaysian Armed Forces in Marang, Terengganu. A total of 206 male military veterans who had never been paroled and who were 40-60 years old voluntarily participated in this study. The sample size was determined according to Krejcie and Morgan¹².

Sociodemographic information: A set of questionnaires was used to collect data regarding sociodemographic information, such as age, marital status, education level, household income, duration of service and latest occupation.

Anthropometric measurement: All anthropometric measurements were performed in accordance with the standard procedure. Height was measured with the participant standing upright without wearing shoes using aSECA Body Meter 208 (SECA, Germany) to the closest 0.1 cm. The TANITA Digital Lithium Scale (HD319; TANITA Corporation, Tokyo, Japan) was used to measure weight to the nearest 0.1 kg. Respondents were measured while wearing light clothing and being barefoot. Body weight and height were required to determine the BMI and were calculated based on weight (kg)/height (m)². BMI is an indicator of nutritional status that is used in adults; the categories were based on Waxman and World Health Assembly¹³ criteria and were defined as follows: underweight: BMI <18.5 kg m^–2; normal: BMI 18.5-24.9 kg m^–2; pre-obese: BMI 25.0-29.9 kg m^–2; class one obese: BMI 30.0-34.9 kg m^–2; class two obese: BMI 35.0-39.9 kg m^–2; and class three obese: BMI≤40.0 kg m^–2. The waist circumference was measured using a flexible, non-stretchable plastic measuring tape to determine waist and hip circumferences to the nearest 0.1 cm. WC was measured using a measuring tape at the mid-point between the inferior margin of the last rib and the iliac crest. Based on the cut-offs recommended for the Asian population¹⁴, individuals with a WC greater than 90 cm are considered to be at greater risk of cardiovascular and diabetic diseases.

Questionnaires: Questionnaires on physical activity habits and physical activity levels were distributed to the subjects. Physical activity habits include the type of activities performed during leisure time, the importance of physical activity for health, level of physical activity, the frequency of physical activity and the duration of exercise. The International Physical Activity Questionnaire (IPAQ) was used to determine the level of physical activity of the respondents¹⁵. The respondents were required to estimate the frequency and time spent on physical activity during the last seven days. Recorded physical activities include physical activity at work, home and leisure activities, transportation from work, exercise or sports activities in their leisure time and time used for sitting. The metabolic equivalent (MET) was used to analyse IPAQ data. The formulas were calculated using the IPAQ¹⁵ formula for calculating physical activity scores, as shown in Table 1. Scores for each type of activity were calculated by multiplying the MET values by the time (min) used and the frequency (days) of the physical activity.

The score is expressed as a MET-min week^–1 score. Total physical activity was calculated by multiplying the total MET-min week^–1 score for all activities. The physical activity score was defined as low with a MET score <600 min week^–1, moderate with a MET score ≥ 600 min week^–1 and high with a MET score ≥3000 min week^–1.

Statistical analysis: All data obtained were analysed using Statistical Package for Social Science software (version 23.0; Armonk. NY, USA). Descriptive statistics including means, standard deviations and percentages were used for physical activity habits, physical activity levels and anthropometric measurement. The Pearson correlation test was used to determine the relationship between BMI and physical activity levels. The level of statistical significance was pre-set at p<0.05.

RESULTS AND DISCUSSION

Anthropometric measurement: The anthropometric measurements involved in this study included height, weight and waist circumference. Table 2 shows the mean anthropometric characteristics of the overall sample of respondents. The mean weight, height, BMI and waist circumference of the respondents were 75.2±143.5 kg, 169.7±6.3, 26.1±4.2 and 83.9±9.7 cm, respectively. A mean BMI above 25 kg m^–2 is considered to be in the overweight category, while a mean waist circumference not exceeding 90 cm is considered to be in the normal waist circumference category. This study found that the majority of the respondents were male (67.8%) and were aged 50-59 years old (62.9%).

Based on Fig. 1, most of the respondents were overweight or obese (42.1%), followed by normal weight (41.1%), while a few respondents (16.8%) belonged to the obese group. According to the findings of Das et al.¹⁶, 73% of the military veterans of the United States of America (U.S.) had BMIs above 25 kg m^–2, while 32.9% had BMIs above 30 kg m^–2. In the U.S., obesity issues have a significant impact on military veterans and most studies have shown that the prevalence of obesity among military veterans had increased⁹. A study conducted in the U.S. also reported that most of their veterans were obese (46.9%) and overweight (37.5%)¹⁷. However, previous studies on U.S. military veterans show that the percentage of obesity was significantly higher than that shown in this study.

In addition, a study conducted in the U.S. on military veterans found that most had problems with overweight or obesity, in comparison to those in the general population of the same gender and age range. They reported having obesity problems and receiving treatment from health professionals due to obesity-related health problems¹⁸. Moreover, overweight and obesity problems have contributed to rising medical costs and the prevalence of both problems are expected to continue rising among U.S. veterans¹⁹. A number of studies on local soldiers have reported that most personnel who were in service suffered from overweight and obesity, which may affect their lives after retirement. The study of Sedek et al.¹¹ on the Royal Malaysian Navy (RMN) personnel showed the prevalence of overweight and obesity to be 29.3% and 7.2%, respectively, while the study of Nadiy et al.¹⁰ on the Malaysian Armed Forces showed a higher prevalence of overweight (32.8%) and obesity (9.3%). Based on a study by Teachman and Tedrow²⁰, U.S. military personnel have a high prevalence of obesity and BMI even though they are still in service. Adebay et al.²¹ reported that most of the Nigerian soldiers aged between 30 and 39 years were overweight and obese. The increase in overweight personnel in the military population has led to various health-related problems and job performance was also affected²².

Waist circumference values greater than 90 cm (35 inches) in men are the cut-off point for Asian populations, which is considered at high risk for cardiovascular disease and diabetes²³. The percentage of subjects who had normal waist circumference (80%) was higher than the percentage of those with risky levels of waist circumference (20%). This indicates that the majority of the respondents are at low risk of cardiovascular disease and diabetes. Higher waist circumference indicates high levels of fat stored around the waist and a high risk of obesity. In this study, a total of 16.8% of the respondents were categorized as obese and most of them had a waist circumference greater than 90 cm. Population studies by Kusher and Blatner²⁴ showed that individuals with high waist circumference have poor health and tend to have a greater risk of cardiovascular disease than do individuals with normal waist circumference.

Physical activity habits: Physical activity plays an important role among older adults because physical activity improves muscle strength, endurance and flexibility to engage in daily activities in life²⁵. Based on Table 3, most of the respondents recorded watching television/listening to the radio (52.6%) and other outdoor physical activities (26.8%) as the most frequent activities in their leisure time, while the rest (a small percentage of 5-8%) stated that they used computers, played sports and slept/rested regularly. The maintenance of good health and healthy lifestyles among older adults is a major challenge. This is because the ageing factor contributes to lower levels of physical activity and limited activity choices²⁶. The study examined the perceptions of the respondents of the importance of physical activity for health and most respondents (89.5%) stated that physical activity is very important for health. In general, regular physical activity improves body composition, glucose homeostasis and insulin sensitivity and helps reduce blood pressure, systemic inflammation and blood clotting. Regular physical activity improves lipid profiles through reduced levels of triglycerides and low-density lipoprotein (LDL) as well as increased levels of high-density lipoprotein²⁷. However, a small percentage of respondents stated that physical activity was not important for health or were unsure about whether physical activity was important for their health (5.3% for both responses). In theory, military personnel live a healthy lifestyle while in service because of the demands of their duties and responsibilities. This lifestyle becomes part of their lives but once they retire, their daily routine may change.

Based on the results of this study, a total of 80.4% respondents assumed they were at a moderate level of physical activity. Littman et al.²⁸ stated that U.S. military veterans reported being less likely to engage in active physical activity after their retirement even though they are reported to be active in the service and this is because during their service, they are forced to abide by the rules in the military camp rather than rely on their own willingness to maintain a healthy lifestyle²⁹.

In addition, the results of this study also showed that the majority of the respondents reported that they exercised for at least 20 min two to three times a week (28.2%) and once a week (26.3%), while some respondents stated that they did not exercise (17.2%). The results of this study showed a drastic decrease in the physical activity of the respondents compared to their previous active life prior to retirement.

Regarding the duration of exercise, more than half of the respondents stated that they exercised for 15-30 min (66%) each session. The respondents who exercised for less than 30 min did so due to their current lifestyle, which differs from their lifestyle during their service, which required them to undergo rigorous physical training. A study conducted in the Netherlands among adult men reported that the average time spent in physical activity decreased in comparison to the time spent exercising 10 years prior³⁰. The study by Haibach et al.³¹ stated that during the early service period, the U.S. military are generally healthier than the general population; however, after the end of their service, their health level is the same or worse than that of the general population due to poor physical activity levels and unhealthy food intake.

Physical activity level: The questionnaire known as the International Physical Activity Questionnaire (IPAQ) was used to measure the physical activity levels of the respondents. The intensity and frequency of physical activity over a 7 day period and the MET scores were recorded. Table 4 shows that the mean metabolic equivalent (MET) scores for high, moderate and walking intensity were, respectively, 991.1±397.3 MET, 964.3±280.9 MET and 490.5±151.8 MET.

Fig. 2 shows a summary of the category of physical activity using the IPAQ for the study respondents. There are three categories of physical activity levels based on the IPAQ: low (<600), medium (≥600) and high (≥3000). Most military veterans involved in this study had a moderate level of physical activity (81.3%) compared to high (15.8%) and low (2.9%) levels.

The percentage of respondents who assumed themselves to be inactive (4.8%) was slightly higher than the percentage indicated by reports of physical activity levels. In addition, the increase in BMI may also influence the decline in the respondents’ levels of physical activity. Based on the study by Littman et al.²⁹, most U.S. veterans have lower levels of physical activity than do those who are in service and they spend more time in sedentary activities. The results of this study are supported by the findings of Smith et al.¹⁷, who showed that the level of physical activity of U.S. military veterans decreased as they retired and returned to normal life, in line with their unhealthy eating habits.

Another study was conducted in the U.S. using the moderate-to-vigorous activity (MVPA) guidelines to determine if their veterans reached the same level of physical activity after retirement. The results show that only 50.4% of their veterans reached the required level of physical activity less than two years after their retirement and this shows a drastic decrease in their level of physical activity²⁹. Physical activity is often influenced by individual lifestyle. It is also a major factor in health and plays an important role in preventing dangerous diseases such as cancer, obesity, diabetes and heart disease, especially in older adults³².

Relationship between BMI and MET physical activity scores: Exercising is a great activity for fitness. Moreover, this activity helps to reduce excess body fat, reduce the risk of chronic disease and reduce daily stressors, including emotional, social and mental stress³³. Based on Table 5, the results showed that there was a negative significant (p<0.01) correlation between BMI and low, moderate and high MET physical activity scores (r = -0.210, p = 0.002; r = -0.030, p<0.001 and r = -0.423, p<0.001, respectively). This indicates that low physical activity levels among respondents contribute to an increase in BMI. This study is in line with the findings of the study conducted by Littman et al.²⁹ on U.S. military veterans, which reported that a decrease in the level of physical activity contributes to an increase in their BMI. The results of this study show that the higher the BMI is, the lower the level of physical activity of the study respondents. This condition may contribute to the higher prevalence of obesity among the respondents after retirement.

CONCLUSION

Most respondents are engaged in sedentary activities, such as watching television/listening to the radio, rather than sports activities. The proportion of respondents who perceived that they had a moderate level of activity was much higher than the proportion of those who perceived that they had a high level of activity. Four-fifths of respondents were in the category of moderate physical activity. There was a significant and negative correlation between BMI and the MET scores of low, moderate and high physical activity levels.

SIGNIFICANCE STATEMENT

This study shows that the physical activity level of military veterans can be of use to the Veterans Association of Malaysia Armed Forces and military health-related agencies, as these data could be used in the initiation of comprehensive programmes to prevent unhealthy lifestyles, low physical activity level and obesity among military veterans. This study will help researchers uncover critical issues related to unhealthy lifestyles faced by military veterans that many researchers have previously been unable to explore. Thus, a new theory on the factors that contribute to obesity can be developed to prevent low levels of physical activity.

ACKNOWLEDGMENTS

The authors would like to thank the subjects, researchers and other individuals involved in the data collection. We convey our special appreciation to Universiti Kebangsaan Malaysia for their support.