Gender-Specific Associations of Neck-Height Ratio, Physical Activity, and Relative Handgrip Strength with Blood Pressure in Young Indian Adults: Implications for Early Cardiovascular Risk Assessment in Women

ABSTRACT IMAGE

INTRODUCTION

Hypertension affects approximately 220 million Indians, contributing significantly to cardiovascular mortality.^[1] The rising prevalence among young adults has been attributed to lifestyle changes, including reduced physical activity and increasing obesity.^[2] Traditional anthropometric measures such as body mass index (BMI) and waist circumference have limitations in evaluating upper-body fat distribution.^[3]

Recent evidence suggests that upper-body subcutaneous adipose tissue contributes to cardiometabolic risks beyond general adiposity.^[4] Neck circumference (NC) and neck-to-height ratio (NtHR) have emerged as promising indicators.^[5] The Framingham Heart Study demonstrated significant associations between NC and cardiometabolic risk factors.^[6] Cross-sectional studies in Thai adults showed NC correlated with hypertension independently of other risk factors.^[7] NtHR offers advantages over traditional measures through simplicity, cultural acceptability, and the ability to account for height variations.^[8] While previous studies showed associations between conventional obesity indices and hypertension in young Indians,^[9] NtHR associations remained unexplored.

Physical activity and muscular strength are independently associated with cardiovascular outcomes.^[10] Relative handgrip strength shows inverse associations with blood pressure (BP) and cardiovascular risk,^[11] particularly significant in young adults for preventing long-term complications. Recent studies suggest that reduced muscular strength in young adulthood may precede clinical hypertension.^[12]

The interrelationship between NtHR, physical activity, and relative handgrip strength in predicting BP remains poorly understood. Understanding these relationships could inform targeted prevention strategies, considering potential gender-specific variations in young adults.

This study aimed to assess relationships between NtHR, physical activity levels, and relative handgrip strength with BP in young Indian adults.

MATERIALS AND METHODS

RESULTS

The characteristics of study population shown in Table 1 demonstrate that there are significant gender differences observed in anthropometric, cardiovascular, and physical function parameters. Males had significantly higher values compared to females.

Males had a higher prevalence of both prehypertension (35.2% vs. 31.2%) and hypertension (11.8% vs. 9.3%) compared to females.

Association of anthropometric and physical function parameters with BP among male participants in Figure 1 shows a positive association between neck-height ratio (NHtR) and various cardiovascular parameters. NHtR showed strong positive correlations with NC, body mass index (BMI), and waist circumference. Notably, NHtR demonstrated strong positive correlations with both systolic and diastolic BP. Relative handgrip strength showed significant negative correlations with most anthropometric measures, particularly with BMI (r = −0.652, P < 0.01). Total physical activity demonstrated modest negative correlations with anthropometric measures and BP parameters, with the strongest negative correlation observed with NHtR (r = −0.376, P < 0.01), indicating NHtR may serve as a valuable screening tool for cardiovascular risk in males, given its strong associations with BP parameters. Higher relative handgrip strength and physical activity appear to have a protective effect against elevated BMI and BP, particularly through its inverse relationship with NHtR.

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Figure 1:

Association of anthropometric and physical function parameters with blood pressure in males (n = 200). (NHtR: Neck height ratio, NC: Neck circumference, BMI: Body mass index, WC: Waist circumferece, HR: Heart rate, SBP: Systolic blood pressure, DBP: Diastolic blood pressure, RHGS: Relative hand grip strength, TPA: Total physical activity)

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Association of anthropometric and physical function parameters with BP among female participants in Figure 2 revealed some distinct characteristics compared to males. NHtR maintained strong positive correlations with NC and demonstrated significant associations with both systolic and diastolic BP. Notable differences from the male population included stronger negative correlations between relative handgrip strength and anthropometric measures, particularly with BMI (r = −0.755, P < 0.01). Total physical activity showed stronger negative correlations in females compared to males, especially with NHtR (r = −0.573, P < 0.01) and systolic BP (r = −0.516, P < 0.01).

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Figure 2:

Association of anthropometric and physical function parameters with blood pressure in females (n = 215). NHtR: Neck height ratio, NC: Neck circumference, BMI: Body mass index, WC: Waist circumferece, HR: Heart rate, SBP: Systolic blood pressure, DBP: Diastolic blood pressure, RHGS: Relative hand grip strength, TPA: Total physical activity

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Multiple regression analysis in Table 2 revealed that NHtR was the strongest predictor of systolic BP in both genders, with slightly higher predictive value in females (β = 0.763) compared to males (β = 0.731). Physical parameters showed notable gender differences in their associations with systolic BP. Relative handgrip strength demonstrated a stronger protective effect in females (β = −0.600) compared to males (β = −0.200). Similarly, total physical activity showed a stronger negative association with systolic BP in females (β = −0.509) than in males (β = −0.320). The overall model explained more variance in females (R² = 0.732) than in males (R² = 0.689).

The area under the receiver operating characteristic curve (ROC) curve (AUC) established optimal cutoff values for NHtR in predicting hypertension and prehypertension across both genders as shown in Table 3. For hypertension, the cutoff values were 20.77 in males (sensitivity: 81.6% and specificity: 78.4%) and 19.87 in females (sensitivity: 84.3% and specificity: 81.2%). For prehypertension, cutoffs were 19.20 in males (sensitivity: 78.8% and specificity: 75.2%) and 18.54 in females (sensitivity: 80.2% and specificity: 77.8%). All AUC values were statistically significant (P < 0.001), indicating good discriminative ability of NHtR for both conditions in both genders.

DISCUSSION

NC is an important indicator of upper-body fat distribution and is associated with potential cardiovascular and respiratory health risks. The relationship between NtHR and BP likely involves multiple pathways. Upper body subcutaneous adipose tissue releases inflammatory cytokines (tumor necrosis factor-α, interleukin-6, and C-reactive protein) that impair endothelial function through reduced nitric oxide bioavailability, increasing vascular resistance. In addition, excess neck adiposity may contribute through mechanical compression of carotid arteries, affecting baroreceptor sensitivity, and predisposing to sleep-disordered breathing with associated sympathetic activation.^[13]

Gender-specific mechanisms may include hormonal influences on fat distribution and vascular reactivity, different adipokine profiles, and variations in muscle fiber composition. The stronger protective effects of physical activity and handgrip strength in females suggest gender-specific cardiovascular responses to lifestyle interventions.

Our findings align with previous studies demonstrating NC associations with cardiovascular risk. Začiragić et al. found NtHR correlated with BP in Bosnian students,^[14] while Kuciene et al. showed high NC increased BP risk in youth.^[15] Our correlations exceeded those reported by Zhou et al. in Chinese adults^[16] and the Framingham heart study,^[6] possibly reflecting ethnic differences in body composition.

The gender-specific patterns observed highlight the importance of sex-specific cardiovascular risk assessment. Stronger associations in females, along with enhanced protective effects of physical activity and handgrip strength, suggest that women may respond more favorably to lifestyle interventions, consistent with systematic reviews reporting greater BP reductions in women.^[17]

Based on ROC analysis, we suggest clinical risk thresholds: males ≥20.77 (hypertension risk) and ≥19.20 (prehypertension risk) and females ≥19.87 and ≥18.54, respectively. NtHR measurement requires only a tape measure, making it valuable for resource-limited settings. This measurement provides physical feedback for patients and can monitor intervention effectiveness.

For clinical implementation, NtHR should complement, not replace, standard BP measurement. Patients exceeding gender-specific thresholds warrant comprehensive cardiovascular assessment and lifestyle counselling. Population screening applications could be particularly valuable in rural or underserved communities.

CONCLUSION

NtHR demonstrates strong predictive value for BP with notable gender-specific patterns in young Indian adults. The stronger associations and protective effects observed in females suggest potential for targeted interventions. These findings support NtHR as an effective, simple cardiovascular screening tool, particularly valuable in resource-constrained settings. Future longitudinal studies should examine causal relationships and intervention effectiveness.