Ultrasound Study Reveals How Smoking, Age and BMI Reshape the Face Forensic Artists Reconstruct

When forensic artists reconstruct a face from a skull, they rely on decades-old average measurements of how thick the soft tissue is at specific points on the human head. Those averages, however, hide a messy biological truth: the padding between bone and skin varies enormously from person to person, shaped by sex, age, body weight and lifestyle. A new study from Slovakia has now added a surprising variable to that list, examining whether cigarette smoking leaves a measurable imprint on the thickness of facial soft tissue, and the answer turns out to be more nuanced, and more sex-specific, than anyone expected.

The research, published in The Science of Nature by a team from the Department of Anthropology at Comenius University in Bratislava, was led by Zuzana Kozáková together with Petra Švábová, Michal Soták, Mária Matláková and Radoslav Beňuš. Their pilot cross-sectional study enrolled 246 adult participants, 176 women and 70 men, and measured facial soft tissue thickness, or FSTT, using B-mode ultrasonography. The technique is a relatively recent addition to the forensic toolkit: instead of measuring tissue depths on cadavers or through expensive imaging such as MRI and computed tomography, ultrasound allows researchers to capture living, breathing faces quickly, safely and with a standardized protocol that has been gaining traction in craniofacial identification since around 2020.

The team measured tissue depth at sixteen anatomical landmarks: eight located along the midline of the face, running from the forehead down to the chin, and eight paired landmarks positioned on both left and right sides of the face, including sites such as the fossa canina, the small depression above the canine tooth where tissue thickness is notoriously variable. This bilateral approach matters because previous work by some of the same authors had shown that head position can subtly alter ultrasound readings, and because asymmetry itself carries forensic information. Each measurement was then fed into a statistical battery that included non-parametric tests, Spearman rank correlations and general linear models, with body mass index and age entered as covariates so that the independent contribution of each factor could be untangled.

The headline finding is that the three variables the researchers probed, body mass index, age and smoking status, do not act uniformly. Instead, their influence depends strongly on both sex and the specific anatomical site. In women, BMI emerged as the dominant predictor of facial tissue thickness, producing effects the authors classified as medium to large across most of the measured landmarks. That is perhaps intuitive: subcutaneous fat is distributed across the face in ways that scale with overall adiposity, and a heavier face is simply a fuller face. Age, by contrast, contributed only modestly to variation in the female sample, with its effects concentrated in the lower face, where soft tissue tends to sag and redistribute over the decades.

In men, the pattern flipped. Age, not BMI, showed the stronger and more consistent association with facial soft tissue thickness, with age-related variation most evident in the midfacial and mandibular regions. This sexual dimorphism in how the face ages and accumulates tissue is not merely an academic curiosity. Forensic facial reconstruction depends on choosing the right tissue depth standards for the unknown individual, and if a male skull is estimated to belong to a middle-aged man, the tissue depths an artist should apply at the midface and jaw may differ systematically from those used for a young man, independently of his weight. Population-specific databases, like the Slovak dataset this team has been building since their earlier 2012 midface study, are what make those calibrated choices possible.

And what about smoking? Given the well-documented effects of tobacco on skin, including premature wrinkling, altered biophysical skin properties, and tobacco-smoke-induced degradation of the extracellular matrix, the researchers had good reason to suspect that chronic smoking might thin or remodel the facial soft tissues in measurable ways. The results, however, were strikingly localized rather than global. In women, conventional smokers did show significantly lower FSTT values than non-smokers, but only at one landmark: the left fossa canina, where the difference reached statistical significance at p = 0.046. Everywhere else, the smoking signal dissolved into the noise. In men, direct comparison between smokers and non-smokers revealed no significant differences in tissue thickness at any of the sixteen landmarks.

The authors are careful about what this means. Overall smoking status was not consistently associated with FSTT in their sample, and they explicitly frame the female fossa canina result as a preliminary association that requires confirmation. The study is a pilot, and its design carries real limitations: the sample is heavily skewed toward women, who outnumbered men 176 to 70, and the researchers themselves state that larger and more balanced samples are needed before any firm conclusions can be drawn. Smoking behavior also correlates with body mass index in population studies, which makes it statistically difficult to isolate a pure smoking effect from the confounding influence of weight, a problem the covariate-based modeling was designed to address but which no observational design can fully eliminate.

Why does a single significant landmark among sixteen matter at all? For forensic facial reconstruction, even localized differences could matter if they are real. The fossa canina is one of the classic tissue-depth points used when clay or digital layers are added over a skull, and it sits in a region of the cheek where tissue thickness helps define the shape of the nasolabial area, one of the most recognizable features of a reconstructed face. If smoking genuinely thins tissue at this site in women, then a reconstruction of a female skull that assumed average tissue depths could subtly misrepresent the cheek contour of a woman who was a lifelong smoker. Conversely, the study’s broader message may be reassuring for forensic practitioners: smoking status, unlike sex, age and BMI, does not appear to demand its own correction factors in tissue depth tables, at least not on current evidence.

The work also fits into a larger methodological shift in forensic anthropology. Traditional FSTT databases, such as the large-scale Caucasian dataset assembled in 2006, were built largely from cadaver needle measurements and later from radiographic imaging. Ultrasound offers a way to build population-specific databases from living volunteers at low cost, and recent studies have applied it to populations ranging from northern Chinese Han to Australians, Brazilians, Iranians and sub-adults in Türkiye, each documenting how sex, age and BMI shape the facial soft tissue envelope differently across populations. The Slovak team’s earlier work measured midface tissue depths and tested the effect of head position on ultrasound readings; the new study extends that program into behavioral variables, a relatively unexplored frontier.

For now, the practical takeaways are measured. Facial reconstruction should continue to prioritize sex, age and BMI as the primary drivers of tissue depth variation, with sex-specific standards applied carefully: BMI dominates in women, age dominates in men. Smoking, despite its visible effects on skin texture and wrinkling, does not currently justify a systematic adjustment in tissue depth standards, though the localized female finding at the left fossa canina is worth watching as larger datasets accumulate. The study also underscores a broader lesson about the human face: it is not a static mask over bone but a living, changing structure that records biology and behavior in unequal measure across its contours. As ultrasound technology spreads through forensic laboratories, the maps of that structure will only grow more detailed, and the faces reconstructed from unidentified remains will, ideally, grow more faithful to the people they once belonged to.

Subject of Research: Effects of BMI, age and smoking on facial soft tissue thickness measured by ultrasound for forensic facial reconstruction

Article Title: Smoking-related variation in facial soft tissue thickness assessed by ultrasound: forensic implications for facial analysis

Article References: Kozáková, Z., Švábová, P., Soták, M., Matláková, M., & Beňuš, R. (2026). Smoking-related variation in facial soft tissue thickness assessed by ultrasound: forensic implications for facial analysis. The Science of Nature, 113(6), Article 126. https://doi.org/10.1007/s00114-026-02173-5

Image Credits: AI Generated

DOI: 10.1007/s00114-026-02173-5

Keywords: facial soft tissue thickness, ultrasonography, forensic facial reconstruction, smoking, body mass index, aging, sexual dimorphism, forensic anthropology, craniofacial identification, Slovak population, pilot study, Comenius University Bratislava