Differences in cancer rates among adults born between 1920 and 1990

Incidence vs. Detection and Mortality

• Multiple commenters stress that rising cancer incidence may largely reflect better and earlier detection, not just more disease.
• Some note that in many developed countries, cancer mortality has been flat or declining despite higher incidence.
• The Lancet study’s age–period–cohort modeling is cited: period effects (e.g., improved diagnostics) vs. birth-cohort effects (changing exposures).
• Others argue detection alone is unlikely to explain increases in only some cancer types, or strong US-specific trends.

Obesity, Lifestyle, and Diet

• Historical obesity data show a sharp rise from ~13% to over 40% of US adults since the 1960s; similar but smaller trends in Europe and elsewhere.
• Obesity is repeatedly mentioned as a major cancer risk factor, tied to sedentary lifestyles, ultra-processed foods, and larger portions.
• Debate over BMI: some say it’s crude and mislabels tall/muscular people; others counter that for most non-athletes it’s reasonably predictive.

Seed Oils and Fats Debate

• One camp claims vegetable seed oils are uniquely harmful and linked to modern metabolic and cancer problems, blaming low-fat/high-sugar dietary shifts and “Big Food.”
• Others counter that evidence does not show commonly used seed oils are harmful when not rancid/trans, and that the anti-seed-oil stance is poorly supported.
• A cited RCT (Minnesota Coronary Survey) vs. a meta-analysis of RCTs are invoked, illustrating conflicting interpretations.
• Trans fats and high-heat degradation of oils are acknowledged as real concerns; some data suggest minimal trans-fat formation below ~200°C.

Environmental & Regulatory Factors

• Suspects mentioned: PFAS, microplastics, synthetic fertilizers, pollution from internal combustion engines, pesticides, and food additives.
• US-specific worries: higher use of certain additives (e.g., brominated vegetable oil, Red No. 3, potassium bromate) that have been restricted elsewhere; some see this as regulatory failure.
• Others caution that many substances are “implicated” as carcinogens without strong evidence; context and dose matter.

Screening, Overdiagnosis, and New Tests

• There is discussion of new blood-based multi-cancer screening using cfDNA methylation (e.g., Galleri), with very high reported specificity.
• Enthusiasts highlight potential for much earlier detection and prevention.
• Critics emphasize overdiagnosis, base-rate fallacy, downstream anxiety, unnecessary biopsies/surgeries, and system-level cost/benefit trade-offs.
• Lowering screening ages (e.g., for breast cancer) is contested: may save some lives but increases harms and costs; “first, do no harm” vs. “screen more” tension.

Healthcare System Incentives (US-focused)

• Several comments argue US insurance structures distort care: insurers and networks, not physicians, often determine treatments.
• Others respond that any system with shared costs needs population-level cost–benefit thresholds; completely doctor–patient–only decision-making is unrealistic.

Specific Cancers and Treatment Progress

• Thyroid cancer incidence is said to be rising strongly while mortality is flat; some suggest overdiagnosis and profitable long-term management.
• Pancreatic and glioblastoma cancers remain highly lethal, but there is optimism about CAR-T and mRNA-based immunotherapies.
• Anecdotes underscore dramatic survival improvements for some cancers (e.g., metastatic melanoma) due to immunotherapy, though many still die.

Statistical Interpretation and Unclear Causes

• Commenters warn against focusing on percentage changes without base rates or age at death; cause-of-death is inherently zero-sum.
• Chains of causality (e.g., drunk driving → crash → blood loss → cardiac arrest) illustrate how “root cause” can be framed at different levels.
• For US cancer trends since the 1990s, obesity, lifestyle, GMOs, PFAS, and food chemicals are all floated; none are clearly established in the thread.
• Overall consensus: incidence is up, mortality often down, lifestyle matters a lot; environmental and systemic contributors remain unclear.