The sociodemographic and anthropometric characteristics of the study population are presented in Table 1. The sample comprised 164,513 participants, with 79,821 women (48.52%) and 84,692 men (51.48%), and had a mean age of 44.38 ± 16.72 years (women: 45.36 ± 16.91 years; men: 43.46 ± 16.49 years). The majority of participants resided in urban areas (81.16%) compared to rural areas (18.84%). Regarding educational level, 42.15% had completed secondary education, 36.38% higher education, 21.24% primary education, and only 0.23% had no formal education. The wealth index distribution showed balanced participation among different quintiles, without marked differences between the poorest (18.31%) and the richest (20.45%).

Sex-specific anthropometric characteristics showed important differences (Table 1). Women presented higher mean BMI (28.31 ± 5.14 kg/m²) compared to men (27.26 ± 4.41 kg/m²), higher WHtR (0.62 ± 0.08 vs 0.57 ± 0.07), but similar WC (93.52 ± 11.77 cm vs 94.27 ± 11.37 cm). Men presented higher systolic blood pressure (127.39 ± 17.69 vs 118.27 ± 19.61 mmHg) and diastolic blood pressure (76.95 ± 12.48 vs 72.61 ± 11.31 mmHg). According to traditional BMI classification, 29.75% of the population presented normal weight, 42.16% overweight, and 28.09% obesity, resulting in a combined prevalence of overweight and obesity of 70.25%. The prevalence of abdominal obesity varied significantly according to the criterion used: 44.75% according to ATP III criteria (≥102 cm in men, ≥88 cm in women) and 68.31% according to IDF criteria (≥90 cm in men, ≥80 cm in women), with women showing substantially higher prevalence than men under both criteria (73.31% vs 26.69% for ATP III; 62.40% vs 37.60% for IDF).

Figure 1 presents smoothed percentile curves for the three anthropometric indicators by age and sex. In panel A (BMI), it is observed that all percentiles follow a characteristic pattern of increase from 20 years until reaching maximum values in middle age (40–50 years), followed by a gradual decline in advanced ages. In women, the 50th percentile (median) increases from ~25 kg/m² at 20 years to 29 kg/m² at 45 years, decreasing to 25 kg/m² at 80 years. In men, the pattern is similar, but with consistently lower values, with the median varying between 24 kg/m² in young adults, 27 kg/m² in middle age, and 24 kg/m² in older adults.

A BMI, B WC, C WHtR ratio. Curves represent 5th, 10th, 25th, 50th, 75th, 85th, 90th, 95th, and 97th percentiles derived from DHS 2015 to 2023 data (n = 385,247).

Panel B (WC) shows similar patterns, with progressive increases until the sixth decade of life. In women, the 50th percentile increases from 85 cm at 20 years to 96 cm at 55–60 years, remaining relatively stable until declining to 88 cm at 80 years. In men, values range from 83 cm in young adults to 95 cm in the sixth decade, declining to 91 cm at advanced ages. Panel C (WHtR) exhibits the same age pattern, with the median in women increasing from 0.55 at 20 years to 0.64 at 55–60 years, while in men it varies from 0.50 to 0.59 in the same age range.

BMI percentiles by age and sex are presented in Table 2. In men, the 50th percentile increased from 24.1 kg/m² in the 20–24 years group to a maximum of 27.1 kg/m² in the 35–44 years groups, remaining stable until 49 years and declining progressively to 24.3 kg/m² in the 80+ years group. The 85th percentile, used as a reference point for overweight, varied from 28.8 kg/m² in the youngest group to 31.6 kg/m² in the 50–54 years group, declining to 28.4 kg/m² in those over 80 years.

In women, the 50th percentile showed a similar pattern, but with consistently higher values, increasing from 25.2 kg/m² at 20–24 years to 28.9 kg/m² in the 45–49 years group, and decreasing to 24.8 kg/m² in the 80+ years group. The 85th percentile varied between 30.6 kg/m² in the youngest group and 34.1 kg/m² in the 45–49 years group, declining to 29.7 kg/m² in those over 80 years.

The upper percentiles (P90, P95, P97) followed similar patterns, with progressive increases until middle age and subsequent declines. Sex differences were more pronounced in the upper percentiles, with women showing values 2–3 kg/m² higher than men in the same age groups.

WC percentiles by age and sex are shown in Table 3. In men, the 50th percentile increased from 83.3 cm in the 20–24 years group to 95.5 cm in the 60–64 years group, followed by a gradual decline to 91.3 cm in the 80+ years group. The 85th percentile showed a similar pattern, varying from 95.5 cm in the youngest group to 107.4 cm in the 60–64 years group.

In women, the 50th percentile increased from 84.8 cm at 20–24 years to 95.5 cm in the 50–59 years groups, remaining relatively stable until 64 years and declining to 87.3 cm in the 80+ years group. The 85th percentile varied between 96.5 cm in the youngest group and 108.2 cm in the 55–59 years group.

Sex differences were less pronounced than in BMI, especially in young ages where values were similar. In middle and advanced ages, women showed slightly higher values in central percentiles, but lower values in upper extreme percentiles.

WHtR percentiles are presented in Table 4. In men, the 50th percentile increased from 0.505 in the 20–24 years group to 0.591 in the 60–64 years group, with subsequent stability. The 85th percentile varied from 0.574 in the youngest group to 0.662 in the 60–64 years group. In the case of women, the 50th percentile showed a more pronounced increase, from 0.554 at 20–24 years to 0.637 in the 55–64 years groups, declining to 0.613 in the 80+ years group. The 85th percentile increased from 0.633 in the youngest group to 0.722 in the 60–64 years group.

BMI percentiles showed systematic differences according to altitude of residence. In men aged 30–34 years, the 50th percentile was 27.5 kg/m² at sea level, 26.3 kg/m² at moderate altitude, and 25.1 kg/m² at high altitude. In women of the same age group, the corresponding values were 27.9 kg/m², 27.3 kg/m², and 26.9 kg/m², respectively. This pattern of decreasing values with higher altitude remained consistent across all age groups and percentiles evaluated (P75, P85, P90, P95, P97).

The differences between extreme altitudes (sea level vs high altitude) in the 50th percentile varied between 2.0 and 3.0 kg/m² in men and 1.5 and 2.5 kg/m² in women, depending on the age group. The upper percentiles (P85, P90, P95) showed similar or slightly greater differences.

WC presented a similar pattern to BMI, with decreasing values at higher altitudes. In men aged 40–44 years, the 50th percentile was 94.9 cm at sea level, 91.9 cm at moderate altitude, and 88.2 cm at high altitude. For women of the same group, the values were 95.7 cm, 93.4 cm, and 91.6 cm, respectively. The differences between sea level and high altitude in the 50th percentile ranged between 4 and 7 cm in men and 3 and 6 cm in women according to age group. In the upper percentiles (P85–P97), the differences remained in similar ranges, with variations of 5–8 cm between extreme altitudes.

The WHtR followed the same decreasing pattern with higher altitude observed in the other indicators. In the 35–39 years group, the 50th percentile in men was 0.577 at sea level, 0.558 at moderate altitude, and 0.543 at high altitude. In women of the same group, the corresponding values were 0.618, 0.602, and 0.592. The differences between extreme altitudes in the 50th percentile varied between 0.030 and 0.050 in men and 0.025 and 0.040 in women according to age. The upper percentiles showed comparable differences, with variations of 0.035–0.055 units between sea level and high altitude.

A continuous altitudinal gradient was observed in the three anthropometric indicators, where moderate altitude values consistently positioned between those of sea level and high altitude. In all cases, the differences between adjacent altitude categories were approximately half of the total difference between extremes. Additionally, the magnitude of altitude differences remained relatively constant across different age groups, although it was slightly greater in middle ages (30–50 years) compared to younger and older groups. The pattern was consistent in both sexes, although absolute differences tended to be slightly greater in men for BMI and WC, while they were similar between sexes for WHtR. Complete altitude-stratified percentile values (P5–P97) for BMI, WC, and WHtR by age and sex are presented in Supplementary Tables S1, S2, and S3, respectively.