Longitudinal Height Growth Patterns Among Children Receiving Menaquinone-7 Supplementation

Background/Objectives: Linear growth in children reflects cumulative influences of nutrition, health, and skeletal development. Vitamin K2, particularly menaquinone-7 (MK-7), plays an important role in bone mineralization, yet evidence regarding its potential relationship with height growth in children remains limited. This study evaluated the association between continuous MK-7 supplementation and longitudinal height growth in children. Methods: A longitudinal observational study was conducted among 1150 apparently healthy children aged 6–14 years in Hanoi, Vietnam (2022–2025), including 613 controls and 537 children receiving MK-7 supplementation. MK-7 was administered orally at 360 µg/day from baseline throughout follow-up. A total of 3491 repeated height measurements were collected. Analyses were stratified according to pubertal stage (no-puberty and pre-puberty). Height gain was summarized according to follow-up duration, and initial mixed-effects models were used to explore longitudinal growth trajectories. Because substantial follow-up imbalance was observed after the first follow-up assessment, the primary regression analyses were subsequently restricted to baseline and first follow-up observations. Multivariable linear regression models evaluated the interaction between MK-7 supplementation and follow-up duration after adjustment for age, sex, baseline body mass index-for-age Z-score, early sleep, and physical activity. Results: Height gain increased significantly with follow-up duration across all analyses (β range: 0.49–0.58 cm/month; all p < 0.001). MK-7 supplementation alone was not independently associated with height gain; however, positive interactions between MK-7 supplementation and follow-up duration were observed in several subgroup analyses. In the overall cohort, the interaction estimate was β = 0.05 cm/month (95% CI: 0.02–0.09). Positive interactions were observed in no-puberty children (β = 0.05; 95% CI: 0.01–0.09) and pre-puberty children (β = 0.06; 95% CI: 0.03–0.09). The largest interaction estimate was observed among pre-puberty boys (β = 0.10; 95% CI: 0.07–0.13), whereas no statistically significant interaction was observed among girls in the pre-puberty subgroup. Conclusions: The findings suggest that continuous MK-7 supplementation may be associated with progressively greater height gain over time rather than an immediate increase in height. The observed associations appeared more evident with longer follow-up duration, particularly among pre-pubertal boys. However, given the observational design and substantial follow-up imbalance between groups, the findings should be interpreted cautiously. Further prospective studies with balanced longitudinal follow-up are needed to clarify the potential relationship between MK-7 supplementation and pediatric linear growth.