Dietary salt reduction and cardiovascular disease rates in India: a mathematical model.

BACKGROUND

Reducing salt intake has been proposed to prevent cardiovascular disease in India. We sought to determine whether salt reductions would be beneficial or feasible, given the worry that unrealistically large reductions would be required, worsening iodine deficiency and benefiting only urban subpopulations.

METHODS AND RESULTS

Future myocardial infarctions (MI) and strokes in India were predicted with a Markov model simulating men and women aged 40 to 69 in both urban and rural locations, incorporating the risk reduction from lower salt intake. If salt intake does not change, we expect ~8.3 million MIs (95% CI: 6.9-9.6 million), 830,000 strokes (690,000-960,000) and 2.0 million associated deaths (1.5-2.4 million) per year among Indian adults aged 40 to 69 over the next three decades. Reducing intake by 3 g/day over 30 years (-0.1 g/year, 25% reduction) would reduce annual MIs by 350,000 (a 4.6% reduction; 95% CI: 320,000-380,000), strokes by 48,000 (-6.5%; 13,000-83,000) and deaths by 81,000 (-4.9%; 59,000-100,000) among this group. The largest decline in MIs would be among younger urban men, but the greatest number of averted strokes would be among rural men, and nearly one-third of averted strokes and one-fifth of averted MIs would be among rural women. Only under a highly pessimistic scenario would iodine deficiency increase (by <0.0001%, ~1600 persons), since inadequate iodized salt access--not low intake of iodized salt--is the major cause of deficiency and would be unaffected by dietary salt reduction.

CONCLUSIONS

Modest reductions in salt intake could substantially reduce cardiovascular disease throughout India.