This study represents a longitudinal analysis of physical examination data collected within 2 months after the Spring Festival holidays in 2018, 2019 and 2020, and the results of a questionnaire on lifestyle behaviours conducted by telephone during the quarantine period. Given that the data were collected at the peak of the COVID-19 epidemic in China, the results of this study can partly reflect the impact of the epidemic on body weight in a healthy population.
In China, the Spring Festival is a popular time to visit friends and relatives and to enjoy dinner together. Many people gain significant weight after the Spring Festival, mainly because there are more opportunities to eat out and the festival food usually contains high levels of oil, salt, fat and calories, which lead to excessive energy intake [5]. Because of the COVID-19 outbreak, many cities, including Wuhan, were locked down from January 23 to the middle of February 2020, which was the Spring Festival holiday in China [6-8]. During this period, people were quarantined at home and restricted from going out. Outdoor activities were greatly reduced or even interrupted, and daily life was irregular. In place of outdoor exercise, some people performed indoor activities, such as jogging, tai chi, aerobics, push-ups, and the use of dumbbells, barbells, and abdominal roller equipment.
Faced with the COVID-19 epidemic, some people developed mental illnesses, including anxiety and depression. In particular, medical staff were under greater work-related and psychological pressures [9]. These individuals are more likely to have unhealthy eating behaviours, such as binge eating and the consumption of more high-energy snacks, in an attempt to reduce anxiety and bipolar symptoms. Psychological pressure and unhealthy lifestyle behaviours may lead to overweight and obesity [10].
The results of this study showed that there was no gain in BMI among those people who had regular check-ups (most of whom were medical workers) after the COVID-19 outbreak. This result may be related to the improvement of participants’ health literacy, including health knowledge and skills, during the epidemic. After the COVID-19 outbreak, information about obese people being more likely to be infected with SARS-CoV-2 was reported in China in a timely and comprehensive manner [2,11]. Lifestyle-related diseases, including cardiovascular disease, hypertension, diabetes, and chronic lung disease [12-14], were also associated with increased severity and mortality in COVID-19 patients. Much broad coverage and the promotion of health education greatly developed people’s understanding of health concepts and improved their basic skills regarding healthy diets and activities. Moreover, an increasing number of people attach importance to physical examinations. People who have regular check-ups are often more concerned about their health and quality of life [15] and are more likely to maintain a healthy weight [16]. Therefore, although the joint prevention and control mechanism used in response to the epidemic had a great impact on people's daily productivity and lifestyles, home quarantine did not cause significant weight gain in the study population.
There was no overall gain in the proportion of people with increased BMI, but 82 (41.6%) participants still showed an increase in BMI after the epidemic. Of them, 43 had no increase in BMI in the previous year; the majority were medical staff, who were often thought to have relatively high rates of health literacy, health awareness, and self-weight perception [17]. In fact, medical staff, the main labour force in the fight against the epidemic in hospitals, had a high risk of infection with SARS-CoV-2 during the COVID-19 outbreak. These workers often suffer from sleep deprivation, anxiety, and depression due to intense and heavy work, which may increase the risk of overweight and obesity [18] and the likelihood of eating late-night snacks [19]. There is evidence that improper timing of eating is an independent risk factor for obesity [20]. In the present study, the proportion of night-time snack eaters in subjects with increased BMI was significantly higher than that in those without increased BMI, and eating night-time snacks increased the risk of higher BMI in women by 5.11 times during the epidemic period (P<0.05). On the issue of healthy weight, the belief that “Doctors do not practice self-care” is still widespread. Therefore, medical staff should also pay attention to weight management.
Strength and limits
This study emphasizes the impact of lifestyle on body weight, especially in medical personnel. Those with an increase in BMI were younger (38.4 (12.9) vs. 45.0 (13.5) years, P=0.005), and more had a habit of night-time snacking (60.3% vs. 40.0%, P=0.018) than those without an increase in BMI.This study has several limitations. First, the physical examination data were obtained from only one hospital, which is not representative of other regions. Data before COVID-19 were not available. Second, the participants were primarily medical personnel, which could lead to selection bias. Third, the questionnaire respondents were younger than those lost to follow-up, which may have contributed to bias. This study is a longitudinal study that reports the changes in BMI of the general population before and after the COVID-19 outbreak using data from three consecutive years of physical examinations.