Emergence of the obesity epidemic: 6-decade visualization with humanoid avatars

Abstract

Background: Visualizations of the emerging obesity epidemic, such as with serial US color prevalence maps, provide graphic images that extend informative public health messages beyond those in written communications. Advances in low-cost 3D optical technology now allow for development of large image databases that include participants varying in race/ethnicity, body mass, height, age, and circumferences. When combined with contemporary statistical methods, these data sets can be used to create humanoid avatar images with prespecified anthropometric features.

Objectives: The current study aimed to develop a humanoid avatar series with characteristics of representative US adults extending over the past 6 decades.

Methods: 3D optical scans were conducted on a demographically diverse sample of 570 healthy adults. Image data were converted to principal components and manifold regression equations were then developed with body mass, height, age, and waist circumference as covariates. Humanoid avatars were generated for representative adults with these 4 characteristics as reported in CDC surveys beginning in 1960-1962 up to 2015-2018.

Results: There was a curvilinear increase in adult US population body mass, waist circumference, and BMI in males and females across the 9 surveys spanning 6 decades. A small increase in average adult population age was present between 1960 and 2018; height changes were inconsistent. A series of 4 avatars developed at ∼20-y intervals for representative males and females reveal the changes in body size and shape consistent with the emergence of the obesity epidemic. An additional series of developed avatars portray the shapes and sizes of males and females at key BMI cutoffs.

Conclusions: New mathematical approaches and accessible 3D optical technology combined with increasingly available large and diverse data sets across the life span now make unique visualization of body size and shape possible on a previously unattainable scale. This study is registered at https://clinicaltrials.gov/ct2/show/NCT03637855 as NCT03637855.

Keywords: adiposity; body mass index; manifold regression; three-dimensional; waist circumference.

FIGURE 1

Body mass, BMI, and WC reported in the 9 CDC population surveys beginning in 1960–1962. The zero time was set at 1960–1962, and values thereafter represent the respective differences (Δ) from time zero. Data are fit with polynomial regression lines. The arrows and associated dates correspond to the image dates presented in Figures 3and 4. WC, waist circumference.

FIGURE 2

Representative humanoid avatars of the average US man at 4 time points between 1960–1962 and 2015–2018 as defined by mean adult population body mass, height, age, and WC. Respective average population BMIs (in kg/m²) are as follows: 25.1, 25.7, 28.0, and 29.5. WC, waist circumference.

FIGURE 3

Representative humanoid avatars of the average US woman at 4 time points between 1960–1962 and 2015–2018 as defined by mean adult population body mass, height, age, and WC. Respective average population BMIs (in kg/m²) are as follows: 24.8, 25.2, 28.3, and 29.8. WC, waist circumference.

FIGURE 4

Humanoid avatars for males ranging in BMI (in kg/m²) from 18.5 to 40. Height and age were set at the 2015–2018 CDC population averages for adult males; BMIs were then varied to derive the body mass values used to generate the 4 avatars shown in the figure.

FIGURE 5

Humanoid avatars for females ranging in BMI (in kg/m²) from 18.5 to 40. Height and age were set at the 2015–2018 CDC population averages for adult females; BMIs were then varied to derive the body mass values used to generate the 4 avatars shown in the figure.