Exploring Craniofacial Anthropometry in the Ethnic Adult Population of Meghalaya, Northeast India: A Cross-Sectional Study

Abstract

Craniofacial anthropometry is important for identity, diagnosis of congenital anomalies etc. The incidence of craniofacial abnormalities is high in the Southeast Asian region. The population of Meghalaya differs in features from other states of Northeast India and the neighbouring East Asia. The objective was to study the craniofacial anthropometric features of the ethnic adults in the Meghalaya state of Northeast India. This cross-sectional study was conducted from 2022 to 2023 in the ENT OPD. OPD patients of Meghalayan ethnicity were included in the study. Head length (HL), head breadth (HB), Cephalic index (CI), intercanthal distance (ICD), lateral canthal distance (LCD) and ear length (EL) were measured. A total of 104 adults were included. The majority of the individuals belonged to the Khasi community 51 (49%) followed by the Garo community 27 (26%) and the Jaintia community 26 (25%). The mean ± S.D age of the total sample population was 29.5 ± 8.4 years. The mean CI of the total sample population was 79.13 (mesocephalic). No statistically significant difference was noted between male-female CI in the total and subpopulation groups. In our study, the common head types were dolichocephalic (29%), brachycephalic (29%), mesocephalic (21%), hyperbrachycephalic (16%) and ultrabrachycephalic (5%). A statistically significant difference was noted between Khasi and Jaintia in HL, HW, CI, LCD; between Khasi and Garo in HL, ICD, LCD and between Garo and Jaintia in HW, CI, ICD. We believe our conventional craniofacial anthropometry data could add to the pool of regional anthropometry data and be used for future scientific purposes like anthropology, maxillofacial surgeries, designing helmets, forensic analysis, and gender differentiation.

Introduction

Anthropometry is the method for assessing the size, composition and proportion of the human body with the advantages of being non-invasive and inexpensive [1]. Craniofacial anthropometry measurements are important for the identity of an individual, forensic analysis, diagnosis of congenital anomalies, facial reconstructive procedures, etc [2]. The use of craniofacial anthropometry measurements is not limited to these but has been extended to study other pathological conditions like obstructive sleep apnoea and craniofacial abnormalities [3, 4]. The incidence of craniofacial abnormalities like fronto-ethmoidal meningocele, hypertelorism, and hypotelorism are high in the Southeast Asian region. The orbits of the patients are typically involved in such cases [4]. The population of Meghalaya is diverse with people present from different ethnic backgrounds. They differ in features from each other and also from other states of Northeast India and neighbouring East Asia. The craniofacial anthropometry varies from population to population and from region to region. Hence a worldwide standard is not possible and rather population-based standards are needed. This study evaluates the craniofacial anthropometry in adults of Meghalaya population. No previous studies have been conducted on the Meghalaya population.

The majority of the Northeast Indian population has Mongoloid features and hence hyperbrachycephalic features are expected [5].

Objective

To study the craniofacial anthropometric features of the ethnic adults in the Meghalaya state of Northeast India.

Materials and methods

This Cross-sectional study was conducted in NEIGRIHMS from 2022 to 2023 over 12 months after obtaining NSAC and Institutional Ethics Committee approval ( in accordance with the Declaration of Helsinki).

• A.Inclusion criteria:
  1. Healthy volunteers belonging to the native population of Meghalaya.
  2. Adults aged 18 years or above of both the genders.

• B.Exclusion criteria:
  1. Volunteers belonging to the non-native population of Meghalaya.
  2. Volunteers who had any history of marriage outside their community in the last 3 family generations.
  3. Volunteers with gross craniofacial abnormalities.
  4. Volunteers who underwent any nasal or facial reconstructive surgery.
  5. Volunteers with any history of trauma to the head or face.

Based on the mean cephalic index of 75.99 with a standard deviation of 4.97 with a precision of 1.3 at a 95% confidence level, the sample size was estimated to be 56 [6].

The sample size was calculated using the formula:

Sample size (N) = Z^2α *SD²/D².

where Z^2α at 95% CI is 1.96, SD = 4.97, Absolute precision = 1.3.

Sample size (N) = 1.96² *4.97²/ 1.3².

= 56 individuals.

However, a total of 104 individuals were included in the study to improve the validity of the results. All volunteers who fulfilled the inclusion criteria were selected by convenient sampling. Informed consent was taken from all participants before including in the study. The study was conducted in confirmation with the Declaration of Helsinki. Spreading calipers were used to measure the anthropometry readings taken in centimetres (cm). Various landmarks were used for the head, eye, and ear. Vertex, Glabella, opisthocranion, euryon, zygion, medial canthus, lateral canthus, superaurale, and subaurale were the landmarks used. The following dimensions were measured. Head circumference (HC), head length (HL), head breadth (HB), intercanthal distance (ICD), lateral canthal distance (LCD), and ear length (EL) were measured.

HC was measured at the level of glabella and opisthocranion.

Between glabella and inion, the greatest anteroposterior diameter was measured as HL.

HW was measured between two euryon points.

ICD was measured between the two medial canthi.

LCD was measured between lateral canthi of both the palpebral fissures.

EL was measured as the distance between the superior and inferior aspects of the ear.

The cephalic index (CI) was calculated (Head width x 100 / Head length). It was used to classify and report the head shapes. William et al. classified head shapes into dolichocephalic with a CI of < 74.9, mesocephalic with a CI of 75-79.9, brachycephalic with a CI of 80-84.9, hyperbrachycephalic type with a CI of 85-89.9 and ultrabrachycephalic type with a CI of ≥ 90 [6–8].

Statistical Analysis

Data was entered in Microsoft Excel 2016 (Microsoft Corp., Redmond, WA, USA) and was analysed using Statistical Package for the Social Sciences (SPSS) version 16 (IBM SPSS Statistics, Armonk, NY, USA). Statistical analysis was done to note any differences in the above indices in the study population.

Independent variables: Age, gender, HC, HL, HB, ICD, LCD, EL.

Dependent variables: Cephalic index.

All the statistical tests were considered statistically significant at a p-value of less than or equal to 0.05.

Results

A total of 104 individuals who satisfied the inclusion criteria were included in the study. The native population of Meghalaya had the population from the following communities. The majority of the individuals belonged to the Khasi community which comprised 51 (49%). It was followed by individuals belonging to Garo community 27 (26%) and Jaintia community 26 (25%). ANOVA was done for all 3 groups and subgroup analysis was done.

The mean ± S.D age of the total sample population was 29.5 ± 8.4 years. The mean ± S.D ages of the Khasi community, Garo, and Jaintia community were 31.7 ± 9.4 years, 27.2 ± 6.1 years, and 27.5 ± 7.5 years respectively.

Table 1 shows the various craniofacial arthrometry measures of individuals of the above communities. A statistically significant difference was noted between the male-female Khasi community in HL, LCD. A statistically significant difference was noted between the male-female Jaintia community in HC. No statistically significant difference was noted between the male and female Garo community. In our study, the mean CI of the total sample population was 79.13 indicating mesocephalic type. The mean CI of the Khasi male and female population were 80.59 and 82.52 respectively indicating brachycephalic type of head. The mean CI of the Garo male and female population were 78.07 and 81.48 respectively indicating mesocephalic type for males and brachycephalic head type for females. The Jaintia male and female had mean CI of 72.48 and 73.74 respectively indicating dolichocephalic head type. No statistically significant difference was noted between male and female gender CI in the total and subpopulation groups. The minimum and maximum values of HL, HW and CI in our study are depicted in Table 2.

Table 1.

Summary of the Craniofacial anthropometry of the study population

Anthropometric variables N = 104	Total sample population N = 104				Khasi n = 51 (49%)			Garo n = 27 (26%)			Jaintia n = 26 (25%)
	Total N = 104 Mean ± SD	Male n = 34 Mean ± SD	Female n = 70 Mean ± SD	p value	Male n = 11 Mean ± SD	Female n = 40 Mean ± SD	p value	Male n = 10 Mean ± SD	Female n = 17 Mean ± SD	p value	Male n = 13 Mean ± SD	Female n = 13 Mean ± SD	p value
Head circumference (cm)	56.25 ± 2.0	56.67 ± 1.56	56.05 ± 2.17	0.140	56.48 ± 1.70	55.85 2.57	0.446	56.73 ± 1.43	56.15 0.97	0.263	57.23 ± 18	55.771.42	0.028*
Head length (cm)	18.99 ± 1.09	19.42 ± 0.89	18.77 ± 1.12	0.004*	18.92 ± 0.82	0.80	0.040*	19.21 ± 1.31	0.86	0.925	20.0 ± 0.68	1.13	0.259
Head width (cm)	14.97 ± 1.06	15.05 ± 1.06	14.93 ± 1.06	0.582	15.23 ± 0.72	1.05	0.764	14.91 ± 1.26	0.97	0.126	14.46 ± 1.13	0.58	0.829
Cephalic index	79.13 ± 7.34	77.75 ± 7.47	79.81 ± 7.23	0.182	80.59 ± 4.47	5.16	0.265	78.07 ± 9.23	6.7	0.319	72.48 ± 7.37	5.63	0.631
Intercanthal distance (cm)	3.01 ± 0.56	2.88 ± 0.61	3.07 ± 0.53	0.099	2.73 ± 0.82	2.99 ± 0.57	0.428	3.41 ± 0.40	3.25 ± 0.42	0.334	2.73 ± 0.44	2.92 ± 0.40	0.254
Lateral canthal distance (cm)	10.64 ± 0.93	10.89 ± 0.91	10.52 ± 0.92	0.055	10.59 ± 1.09	10.10 ± 0.72	0.030*	11.0 ± 0.83	10.6 ± 0.81	0.234	11.38 ± 0.65	11.11 ± 1.04	0.438
Ear length (cm)	6.06 ± 0.51	6.10 ± 0.60	6.03 ± 0.46	0.505	6.29 ± 0.73	5.98 ± 0.45	0.084	6.165 ± 0.62	5.8 ± 0.63	0.154	6.19 ± 0.38	6.04 ± 0.14	0.187

cm-centimetre, SD-Standard Deviation, *significant p value

Table 2.

Craniofacial anthropometry of the study population

Parameters	Total N = 104		Jaintia n = 26		Garo n = 27		Khasi n = 51
	Male n = 34	Female n = 70	Male n = 13	Female n = 13	Male n = 10	Female n = 17	Male n = 11	Female n = 40
Head length (cm)
Minimum Maximum	17.00 21.00	16.50 21.00	19.00 21.00	17.00 21.00	17.50 20.50	17.00 21.00	54.00 60.00	16.50 19.50
Head width (cm)
Minimum Maximum	11.50 17.00	13.50 18.50	13.00 17.00	14.00 16.00	14.00 17.00	11.50 17.00	14.50 16.50	13.50 18.50
Cephalic index
Minimum Maximum	57.50 94.11	66.67 94.87	61.90 89.47	66.67 84.21	70.00 89.47	57.50 94.11	74.36 86.84	73.68 94.87

cm-centimetre

In our study, the most common head types were dolichocephalic type and brachycephalic type each constituting 29%. It was followed by mesocephalic type (21%), hyperbrachycephalic type (16%) and ultrabrachycephalic type (5%). Among the male population, the most common head type was the dolichocephalic type and among the females, the most common type was the brachycephalic type as depicted in Table 3.

Table 3.

Distribution of head types among the study population

Gender N = 104	Head shape type n (%)
	Dolichocephalic n = 30 (29%)	Mesocephalic n = 22 (21%)	Brachycephalic n = 30 (29%)	Hyperbrachycephalic n = 17 (16%)	Ultrabrachycephalic n = 5 (5%)
Male n = 34 (33%)	13 (38%)	8 (24%)	6 (18%)	7 (20%)	0
Female n = 70 (67%)	17 (24.3%)	14 (20%)	24 (34.3%)	10 (14.3%)	5 (7%)

Figure 1 shows the distribution of head types among the Jaintia, Garo and Khasi communities in our study population. Among the Jaintia, dolichocephalic (69%) was the common type; among the Garo, dolichocephalic (30%) and brachycephalic types (30%) were common and in the Khasi, brachycephalic head type (39%) was the common type.

Fig. 1.

Head type distribution in subpopulation groups

Table 4 shows the comparison of the anthropometric variables among the ethnic population of Meghalaya. A statistically significant difference was noted between the Khasi community and the Jaintia community in HL, HW, CI and LCD. A statistically significant difference was noted between the Khasi community and the Garo community in HL, ICD and LCD. Between Garo and Jaintia communities a statistically significant difference was noted in HW, CI and ICD.

Table 4.

Comparison of the anthropometric variables among the ethnic population of Meghalaya

Dependent Variable	(I) tribe	(J) tribe	Mean Difference (I-J)	Std. Error	p value
Head circumference (cm)	1	2	− 0.01852	0.55200	1.000
	1	3	0.51373	0.48411	0.873
	2	3	0.53224	0.47813	0.805
Head length (cm)	1	2	0.56624	0.26095	0.097
	1	3	1.32572**	0.22885	0.000*
	2	3	0.75948**	0.22603	0.003*
Head width (cm)	1	2	− 0.76211**	0.28091	0.024*
	1	3	− 0.72398**	0.24636	0.012*
	2	3	0.03813	0.24332	1.000
Cephalic index	1	2	-6.22447**	1.76229	0.002*
	1	3	-8.99641**	1.54554	0.000*
	2	3	-2.77195	1.52647	0.217
Intercanthal distance (cm)	1	2	− 0.52493**	0.14695	0.002*
	1	3	− 0.10445	0.12888	1.000
	2	3	0.42048**	0.12729	0.004*
Lateral canthal distance (cm)	1	2	0.39815	0.23002	0.260
	1	3	1.04000**	0.20241	0.000*
	2	3	0.64185**	0.19993	0.005*
Ear length	1	2	0.08575	0.14148	1.000
	1	3	0.06637	0.12408	1.000
	2	3	− 0.01939	0.12255	1.000

cm-centimetre; 1-Jaintia, 2- Garo, 3-khasi;

**significant mean difference between ethnic communities;^* significant p value

Discussion

Anthropometry is the measure of the size, proportion, and composition of the human body. It is a non-invasive technique. Craniofacial and nasofacial anthropometry deal with the measurements of the head and the facial and nasal features respectively. Cephalometry deals specifically with measurements of the head [9]. The craniofacial and nasofacial anthropometry is useful in forensic analysis, facial reconstruction, pathophysiology of obstructive sleep apnoea, and craniofacial abnormalities [3, 4]. Craniofacial anthropometry is also a useful indicator of newborn health [2].

The cephalic index varies significantly from one population to another. It is important to differentiate individuals of different gender and geography and thus has a role in anthropology [6, 8]. The craniofacial and nasofacial anthropometry of each population group is needed for larger applications in the medical field [10]. In our study, the mean CI of the total sample population was 79.13 indicating mesocephalic type. This was contrary to our research hypothesis. However, the CI of the subpopulations i.e. Khasi male and female population had brachycephalic type of head. The Garo female population showed similar findings. This could indicate a different anthropological origin of the Khasi population. The above statement should be validated with large sample-sized studies in the Khasi population.

In a study by Thomas, 150 participants from South India and 150 participants from North East India were studied. The CI of the participants from South India was 76.47 and from North East India was 84.16 indicating mesocephalic and brachycephalic types respectively [11]. This was in contrast to our finding as Meghalaya is one of the Northeastern states in India. This could be possibly explained by the fact that in the above study by Thomas, there can be a possible over-generalization of the entire North East India as one group and the entire South India as one group. North East India is composed of 8 different states and South India of 5 different states with heterogenous populations with each state having their characteristics [12]. With no previous anthropometry studies on the population of Meghalaya we believe our study can shed some light on the same.

The mean CI of the population in our study was similar to studies from other Indian states of South Kerala, Madhya Pradesh, and Maharashtra and studies from Sri Lanka, Nepal, and West Africa which had mesocephalic type of heads [6, 13–17]. The mean CI in other studies of the population of the Indian states of Punjab, Andhra Pradesh, Gujarat, and other regions like North Brazil had a brachycephalic type of head [18–21]. The common head type among the males and females in our study population was dolichocephalic and brachycephalic type respectively each constituting 29%. A similar finding of dolichocephalic head type predominance in the male population was seen in other studies from Nepal and Sri Lanka [6, 16]. Brachycephalic head type predominance in the female population was seen in other studies from the Indian States of South Kerala, Punjab, Andhra Pradesh; and Sri Lanka [14, 16, 18, 19].

The mean HL in our study was 19.42 ± 0.89 cm and 18.77 ± 1.12 cm for males and females respectively. This difference was statistically significant with a p-value of < 0.05. The minimum and maximum HL in our study ranged from 17.00 cm to 21.00 cm among males and 16.50 to 21.00 cm among females. This was more compared to the HL reported in studies from North India and Nepal [6, 18].

The mean HW in our study was 15.05 ± 1.06 cm and 14.93 ± 1.06 cm among the males and females respectively. This difference was not statistically significant. The minimum and maximum HW in our study ranged from 11.50 cm to 17.00 cm among males and 13.50 to 18.50 cm among females. This was similar to the study population from North India but more compared to the study population from Nepal [6, 18].

Table 5 shows the comparison of the cephalic indices and common head types of various populations.

Table 5.

Comparison of the Cephalic index among various populations

Authors	Population (Gender)	Mean CI (Head type)	Common Head type
Present study	Meghalaya, India (Male/Female)	77.75/ 79.81 (Mesocephalic/ Mesocephalic)	Dolichocephalic/Brachycephalic
Ranga and Mallika [14]	South Kerala, India (Male/Female)	77.1/ 78.4 (Mesocephalic/ Mesocephalic)	Mesocephalic/ Brachycephalic
Mayura Setiya et al. [13]	Madhya Pradesh, India (Male/Female)	77.65/78.13 (Mesocephalic/ Mesocephalic)	Mesocephalic/Mesocephalic
Khatun Sanzida [6]	Tharu, Nepal (Male/Female)	76.22/75.78 (Mesocephalic/ Mesocephalic)	Dolichocephalic/Dolichocephalic
Sultan et al. [15]	Maharashtra, India (Male/Female)	79.12/ 78.67 (Mesocephalic/ Mesocephalic)	Mesocephalic/Mesocephalic
Seema and Verma [18]	Punjab, India (Male/Female)	80.52/84.32 (Brachycephalic/Brachycephalic)	Brachycephalic/Brachycephalic
Kumari et al. [19]	Andhra Pradesh, India (Male/Female)	80.21/79.25 (Brachycephalic/Mesocephalic)	Mesocephalic/Brachycephalic
Gujaria and Salve [20]	Gujarat, India (Male/Female)	80.42/81.20 (Brachycephalic/Brachycephalic)	Mesocephalic/Mesocephalic
Yagain et al. [22]	Indians (Male/Female)	77.92/80.85 (Mesocephalic/Brachycephalic)	Brachycephalic/Brachycephalic
Alves et al. [21]	North Brazil (Mean value)	80.93 (Brachycephalic)	Mesocephalic
Alves et al. [21]	South Brazil (Mean value)	79.06 (Mesocephalic)	Mesocephalic
Ilayperuma et al. [16]	Sri Lanka (Male/Female)	78.04/ 79.32 (Mesocephalic/Mesocephalic)	Dolichocephalic/Brachycephalic
Odokuma et al. [17]	West Africa (Male/Female)	77.67/78.14 (Mesocephalic/Mesocephalic)	Mesocephalic/Mesocephalic

CI-Cephalic index

In a study of Sikkimese newborns by P Sinha et al. the mean cephalic index in males and females were 90.87 and 88.67 respectively [2]. This was in contrast to other Indian population studies mentioned in Table 5. The probable reason may be because the study population was newborn and the adult head shape might vary in the same population. Some researchers compare the anthropologic variables with intelligence and anthropometric variables of older generations with newer generations; of different ethnicities and populations [6, 23]. We believe this study is expected to add to the data for such purposes.

Some researchers have found a positive relation between the CI and the thickness of the skull especially the parietal bone. In dolichocephalic and mesocephalic head-type individuals, the parietal bone thickness is more in the middle and posterior thirds. This is significant especially when the skull is used as a source of bone graft or a site for implantation [8, 24]. Few authors have studied the role of computed tomography scans, magnetic resonance scans, and digital photography in craniofacial anthropometry [5, 25, 26]. The inherent risk of exposure to radiation, cost, and availability are limitations to such types of anthropometry.

The strength of the study is that no previous studies have been done on the ethnic population of the Northeast Indian state of Meghalaya. The study has been done using a non-invasive, cost-effective, and commonly used tool without any risk of radiation exposure. We believe this study could add to the pool of regional anthropometry data for future anthropological and medical applications. The limitation of the study is the relatively small sample size population. Hence a large sample-sized population study is recommended on our population for validation of our results.

Conclusion

The common type of head in our study population was dolichocephalic and brachycephalic. It was followed by mesocephalic, hyperbrachycephalic and ultrabrachycephalic head types. Although anthropometry studies based on radiological scans and digital imaging are emerging, we believe our conventional anthropometry data can be used for future scientific purposes like anthropology, maxillofacial surgeries, designing helmets, forensic analysis, and gender differentiation. Our study signifies the need for population-based anthropometric measurements as even in the same nation the head type varies from region to region.

Funding

None.

Data Availability

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Declarations

Conflict of interest

None.