Development of health and healthy lifestyle behaviors in adults before and during the COVID-19 pandemic: a longitudinal study

The COVID-19 pandemic has led to large-scale societal changes in many countries. Governments 
worldwide have introduced substantial restrictions to people’s movements [1], and such lockdown 
measures could have large impacts on health and health inequalities [2, 3]. While some impacts 
observed during the pandemic could arise from the direct effect of the infection on health [4], 
lockdown measures and restrictions themselves could also have consequences for (mental) health 
and health-related lifestyle behaviors. However, these impacts are difficult to interpret when prepandemic information is lacking. For example, during the COVID-19 pandemic, concerns have been 
repeatedly raised about potentially long-lasting harms to mental health [5]. A recent review of crosssectional studies concerning mental health outcomes found there was a relatively high prevalence of 
symptoms of anxiety and depression, insomnia, and increased stress during the first months of the
COVID-19 pandemic [6]. However, findings from a recent review of longitudinal studies examining 
the same individuals before and during the pandemic show that there was a small increase in mental 
health symptoms soon after the outbreak of the COVID-19 pandemic that decreased thereafter. By 
mid-2020 mental health symptoms were comparable to pre-pandemic levels among most population 
sub-groups and symptom types [7]. In addition, changes in mental health were less pronounced 
among people with pre-existing mental health conditions and overall, there was no statistically 
significant change in mental symptoms in this group. This underlines the need for pre-pandemic data 
for an adequate interpretation of results obtained during the pandemic.
Besides mental health, health-related behaviors such as alcohol consumption, smoking, physical 
activity (PA), and eating behavior have similarly been found to be subject to rapid change in either 
direction during the COVID-19 pandemic[8-12]. For example, a shift towards unhealthy eating 
behaviors was seen, characterized by an increased snack frequency and a preference for sweets and 
ultra-processed food rather than fruits, vegetables, and fresh food [13]. Additionally, an increased 
alcohol consumption was found in different countries, and decreases in PA levels have been reported
[13, 14]. Increased stress during lockdowns could increase tobacco, alcohol and food consumption, 
[15, 16] while greater awareness of health risks, reduced availability and reduced social contacts 
could lead to lower consumption.
A large part of the research on the impact of COVID on health and health related behavior is crosssectional. Many cross-sectional studies based their results on change in health behavior by asking 
respondents themselves if these behaviors had changed due to the pandemic [17-19]. However, 
although respondents report a subjective change in health or health related behavior, this may not 
reflect their actual behavior. For example, in a study on PA in the Netherlands, cross-sectional 
findings showed that, although many respondents reported to be less physically active due to the 
pandemic, PA levels were not lower compared to before the pandemic [20]. Moreover, because of
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Date 15-7-2019
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the nature of cross-sectional studies we cannot say anything about individual changes in health and 
health related behavior (patterns), or of the causal order of the changes. Neither can we examine 
groups of individuals who display different patterns of behavior with cross-sectional data. For
example some people may be exercising more during the lockdown, while others exercise less. At the 
population level no effect may be seen, so important impacts of the pandemic may be missed. To 
truly understand the impact of the COVID-19 pandemic, longitudinal research is needed to examine 
patterns in health and health related behavior over time, before and during the pandemic, and 
determinants of these patterns. 
Therefore, the overall aim of this study is to examine patterns of (mental) health and healthy lifestyle 
behaviors during the COVID-19 pandemic taking into account pre pandemic patterns of behavior and 
health. This knowledge can help to assess the long-term impact of the pandemic on public health.
Additionally, this will provide insight in subgroups that are more vulnerable to unfavorable changes.